/*
Copyright 2015 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package podautoscaler

import (
	"context"
	"fmt"
	"math"
	goruntime "runtime"
	"strings"
	"sync"
	"testing"
	"time"

	autoscalingv1 "k8s.io/api/autoscaling/v1"
	autoscalingv2 "k8s.io/api/autoscaling/v2"
	v1 "k8s.io/api/core/v1"
	k8serrors "k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/api/meta/testrestmapper"
	"k8s.io/apimachinery/pkg/api/resource"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/runtime/schema"
	"k8s.io/apimachinery/pkg/util/wait"
	"k8s.io/apimachinery/pkg/watch"
	utilfeature "k8s.io/apiserver/pkg/util/feature"
	"k8s.io/client-go/informers"
	"k8s.io/client-go/kubernetes/fake"
	scalefake "k8s.io/client-go/scale/fake"
	core "k8s.io/client-go/testing"
	featuregatetesting "k8s.io/component-base/featuregate/testing"
	metricstestutil "k8s.io/component-base/metrics/testutil"
	"k8s.io/kubernetes/pkg/api/legacyscheme"
	autoscalingapiv2 "k8s.io/kubernetes/pkg/apis/autoscaling/v2"
	"k8s.io/kubernetes/pkg/controller"
	"k8s.io/kubernetes/pkg/controller/podautoscaler/metrics"
	"k8s.io/kubernetes/pkg/controller/podautoscaler/monitor"
	"k8s.io/kubernetes/pkg/controller/util/selectors"
	"k8s.io/kubernetes/pkg/features"
	"k8s.io/kubernetes/test/utils/ktesting"
	cmapi "k8s.io/metrics/pkg/apis/custom_metrics/v1beta2"
	emapi "k8s.io/metrics/pkg/apis/external_metrics/v1beta1"
	metricsapi "k8s.io/metrics/pkg/apis/metrics/v1beta1"
	metricsfake "k8s.io/metrics/pkg/client/clientset/versioned/fake"
	cmfake "k8s.io/metrics/pkg/client/custom_metrics/fake"
	emfake "k8s.io/metrics/pkg/client/external_metrics/fake"
	"k8s.io/utils/ptr"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	_ "k8s.io/kubernetes/pkg/apis/apps/install"
	_ "k8s.io/kubernetes/pkg/apis/autoscaling/install"
)

// From now on, the HPA controller does have history in it (scaleUpEvents, scaleDownEvents)
// Hence the second HPA controller reconcile cycle might return different result (comparing with the first run).
// Current test infrastructure has a race condition, when several reconcile cycles will be performed
//    while it should be stopped right after the first one. And the second will raise an exception
//    because of different result.

// This comment has more info: https://github.com/kubernetes/kubernetes/pull/74525#issuecomment-502653106
// We need to rework this infrastructure:  https://github.com/kubernetes/kubernetes/issues/79222

var statusOk = []autoscalingv2.HorizontalPodAutoscalerCondition{
	{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededRescale"},
	{Type: autoscalingv2.ScalingActive, Status: v1.ConditionTrue, Reason: "ValidMetricFound"},
	{Type: autoscalingv2.ScalingLimited, Status: v1.ConditionFalse, Reason: "DesiredWithinRange"},
}

// statusOkWithOverrides returns the "ok" status with the given conditions as overridden
func statusOkWithOverrides(overrides ...autoscalingv2.HorizontalPodAutoscalerCondition) []autoscalingv2.HorizontalPodAutoscalerCondition {
	resv2 := make([]autoscalingv2.HorizontalPodAutoscalerCondition, len(statusOk))
	copy(resv2, statusOk)
	for _, override := range overrides {
		resv2 = setConditionInList(resv2, override.Type, override.Status, override.Reason, "%s", override.Message)
	}

	// copy to a v1 slice
	resv1 := make([]autoscalingv2.HorizontalPodAutoscalerCondition, len(resv2))
	for i, cond := range resv2 {
		resv1[i] = autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   cond.Type,
			Status: cond.Status,
			Reason: cond.Reason,
		}
	}

	return resv1
}

func alwaysReady() bool { return true }

type fakeResource struct {
	name       string
	apiVersion string
	kind       string
}

type testCase struct {
	sync.Mutex
	minReplicas     int32
	maxReplicas     int32
	specReplicas    int32
	statusReplicas  int32
	initialReplicas int32
	scaleUpRules    *autoscalingv2.HPAScalingRules
	scaleDownRules  *autoscalingv2.HPAScalingRules

	// CPU target utilization as a percentage of the requested resources.
	CPUTarget                    int32
	CPUCurrent                   int32
	verifyCPUCurrent             bool
	reportedLevels               []uint64
	reportedCPURequests          []resource.Quantity
	reportedPodReadiness         []v1.ConditionStatus
	reportedPodStartTime         []metav1.Time
	reportedPodPhase             []v1.PodPhase
	reportedPodDeletionTimestamp []bool
	scaleUpdated                 bool
	statusUpdated                bool
	eventCreated                 bool
	verifyEvents                 bool
	useMetricsAPI                bool
	metricsTarget                []autoscalingv2.MetricSpec
	expectedDesiredReplicas      int32
	expectedConditions           []autoscalingv2.HorizontalPodAutoscalerCondition
	// Channel with names of HPA objects which we have reconciled.
	processed chan string

	// expected results reported to the mock monitor at first.
	expectedReportedReconciliationActionLabel     monitor.ActionLabel
	expectedReportedReconciliationErrorLabel      monitor.ErrorLabel
	expectedReportedMetricComputationActionLabels map[autoscalingv2.MetricSourceType]monitor.ActionLabel
	expectedReportedMetricComputationErrorLabels  map[autoscalingv2.MetricSourceType]monitor.ErrorLabel
	checkDesiredReplicaMetric                     bool

	// expectedReconciliationCount specifies the minimum number of reconciliations to wait for.
	// This verifies that reconciliationsTotal counter metric is incremented on each cycle.
	// The actual count may be higher; we only verify it's at least this value.
	expectedReconciliationCount int
	// expectedMetricComputationCounts specifies the minimum computation count per metric type.
	// This verifies that metricComputationTotal counter metric is incremented for each
	// metric type on each reconciliation. The actual counts may be higher.
	expectedMetricComputationCounts map[autoscalingv2.MetricSourceType]int

	// Target resource information.
	resource *fakeResource

	// Last scale time
	lastScaleTime *metav1.Time

	// override the test clients
	testClient        *fake.Clientset
	testMetricsClient *metricsfake.Clientset
	testCMClient      *cmfake.FakeCustomMetricsClient
	testEMClient      *emfake.FakeExternalMetricsClient
	testScaleClient   *scalefake.FakeScaleClient

	recommendations   []timestampedRecommendation
	hpaSelectors      *selectors.BiMultimap
	initialConditions []autoscalingv2.HorizontalPodAutoscalerCondition

	verifyReconciliationDuration     bool
	verifyMetricComputationDurations bool
}

// Needs to be called under a lock.
func (tc *testCase) computeCPUCurrent() {
	if len(tc.reportedLevels) != len(tc.reportedCPURequests) || len(tc.reportedLevels) == 0 {
		return
	}
	reported := 0
	for _, r := range tc.reportedLevels {
		reported += int(r)
	}
	requested := 0
	for _, req := range tc.reportedCPURequests {
		requested += int(req.MilliValue())
	}
	tc.CPUCurrent = int32(100 * reported / requested)
}

func init() {
	// set this high so we don't accidentally run into it when testing
	scaleUpLimitFactor = 8
}

func (tc *testCase) prepareTestClient(t *testing.T) (*fake.Clientset, *metricsfake.Clientset, *cmfake.FakeCustomMetricsClient, *emfake.FakeExternalMetricsClient, *scalefake.FakeScaleClient) {
	logger, _ := ktesting.NewTestContext(t)
	namespace := "test-namespace"
	hpaName := "test-hpa"
	podNamePrefix := "test-pod"
	labelSet := map[string]string{"name": podNamePrefix}
	selector := labels.SelectorFromSet(labelSet).String()

	tc.Lock()

	tc.scaleUpdated = false
	tc.statusUpdated = false
	tc.eventCreated = false
	tc.processed = make(chan string, 100)
	if tc.CPUCurrent == 0 {
		tc.computeCPUCurrent()
	}

	if tc.resource == nil {
		tc.resource = &fakeResource{
			name:       "test-rc",
			apiVersion: "v1",
			kind:       "ReplicationController",
		}
	}
	tc.Unlock()

	fakeClient := &fake.Clientset{}
	fakeClient.AddReactor("list", "horizontalpodautoscalers", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		tc.Lock()
		defer tc.Unlock()
		var behavior *autoscalingv2.HorizontalPodAutoscalerBehavior
		if tc.scaleUpRules != nil || tc.scaleDownRules != nil {
			behavior = &autoscalingv2.HorizontalPodAutoscalerBehavior{
				ScaleUp:   tc.scaleUpRules,
				ScaleDown: tc.scaleDownRules,
			}
		}
		hpa := autoscalingv2.HorizontalPodAutoscaler{
			ObjectMeta: metav1.ObjectMeta{
				Name:      hpaName,
				Namespace: namespace,
			},
			Spec: autoscalingv2.HorizontalPodAutoscalerSpec{
				ScaleTargetRef: autoscalingv2.CrossVersionObjectReference{
					Kind:       tc.resource.kind,
					Name:       tc.resource.name,
					APIVersion: tc.resource.apiVersion,
				},
				MinReplicas: &tc.minReplicas,
				MaxReplicas: tc.maxReplicas,
				Behavior:    behavior,
			},
			Status: autoscalingv2.HorizontalPodAutoscalerStatus{
				CurrentReplicas: tc.specReplicas,
				DesiredReplicas: tc.specReplicas,
				LastScaleTime:   tc.lastScaleTime,
				Conditions:      tc.initialConditions,
			},
		}
		// Initialize default values
		autoscalingapiv2.SetDefaults_HorizontalPodAutoscalerBehavior(&hpa)

		obj := &autoscalingv2.HorizontalPodAutoscalerList{
			Items: []autoscalingv2.HorizontalPodAutoscaler{hpa},
		}

		if tc.CPUTarget > 0 {
			obj.Items[0].Spec.Metrics = []autoscalingv2.MetricSpec{
				{
					Type: autoscalingv2.ResourceMetricSourceType,
					Resource: &autoscalingv2.ResourceMetricSource{
						Name: v1.ResourceCPU,
						Target: autoscalingv2.MetricTarget{
							Type:               autoscalingv2.UtilizationMetricType,
							AverageUtilization: &tc.CPUTarget,
						},
					},
				},
			}
		}
		if len(tc.metricsTarget) > 0 {
			obj.Items[0].Spec.Metrics = append(obj.Items[0].Spec.Metrics, tc.metricsTarget...)
		}

		if len(obj.Items[0].Spec.Metrics) == 0 {
			// manually add in the defaulting logic
			obj.Items[0].Spec.Metrics = []autoscalingv2.MetricSpec{
				{
					Type: autoscalingv2.ResourceMetricSourceType,
					Resource: &autoscalingv2.ResourceMetricSource{
						Name: v1.ResourceCPU,
					},
				},
			}
		}

		return true, obj, nil
	})

	fakeClient.AddReactor("list", "pods", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		tc.Lock()
		defer tc.Unlock()

		obj := &v1.PodList{}

		specifiedCPURequests := tc.reportedCPURequests != nil

		numPodsToCreate := int(tc.statusReplicas)
		if specifiedCPURequests {
			numPodsToCreate = len(tc.reportedCPURequests)
		}

		for i := 0; i < numPodsToCreate; i++ {
			podReadiness := v1.ConditionTrue
			if tc.reportedPodReadiness != nil {
				podReadiness = tc.reportedPodReadiness[i]
			}
			var podStartTime metav1.Time
			if tc.reportedPodStartTime != nil {
				podStartTime = tc.reportedPodStartTime[i]
			}

			podPhase := v1.PodRunning
			if tc.reportedPodPhase != nil {
				podPhase = tc.reportedPodPhase[i]
			}

			podDeletionTimestamp := false
			if tc.reportedPodDeletionTimestamp != nil {
				podDeletionTimestamp = tc.reportedPodDeletionTimestamp[i]
			}

			podName := fmt.Sprintf("%s-%d", podNamePrefix, i)

			reportedCPURequest := resource.MustParse("1.0")
			if specifiedCPURequests {
				reportedCPURequest = tc.reportedCPURequests[i]
			}

			pod := v1.Pod{
				Status: v1.PodStatus{
					Phase: podPhase,
					Conditions: []v1.PodCondition{
						{
							Type:               v1.PodReady,
							Status:             podReadiness,
							LastTransitionTime: podStartTime,
						},
					},
					StartTime: &podStartTime,
				},
				ObjectMeta: metav1.ObjectMeta{
					Name:      podName,
					Namespace: namespace,
					Labels: map[string]string{
						"name": podNamePrefix,
					},
				},

				Spec: v1.PodSpec{
					Containers: []v1.Container{
						{
							Name: "container1",
							Resources: v1.ResourceRequirements{
								Requests: v1.ResourceList{
									v1.ResourceCPU: *resource.NewMilliQuantity(reportedCPURequest.MilliValue()/2, resource.DecimalSI),
								},
							},
						},
						{
							Name: "container2",
							Resources: v1.ResourceRequirements{
								Requests: v1.ResourceList{
									v1.ResourceCPU: *resource.NewMilliQuantity(reportedCPURequest.MilliValue()/2, resource.DecimalSI),
								},
							},
						},
					},
				},
			}
			if podDeletionTimestamp {
				pod.DeletionTimestamp = &metav1.Time{Time: time.Now()}
			}
			obj.Items = append(obj.Items, pod)
		}
		return true, obj, nil
	})

	fakeClient.AddReactor("update", "horizontalpodautoscalers", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		handled, obj, err := func() (handled bool, ret *autoscalingv2.HorizontalPodAutoscaler, err error) {
			tc.Lock()
			defer tc.Unlock()

			obj := action.(core.UpdateAction).GetObject().(*autoscalingv2.HorizontalPodAutoscaler)
			assert.Equal(t, namespace, obj.Namespace, "the HPA namespace should be as expected")
			assert.Equal(t, hpaName, obj.Name, "the HPA name should be as expected")
			assert.Equal(t, tc.expectedDesiredReplicas, obj.Status.DesiredReplicas, "the desired replica count reported in the object status should be as expected")
			if tc.verifyCPUCurrent {
				if utilization := findCpuUtilization(obj.Status.CurrentMetrics); assert.NotNil(t, utilization, "the reported CPU utilization percentage should be non-nil") {
					assert.Equal(t, tc.CPUCurrent, *utilization, "the report CPU utilization percentage should be as expected")
				}
			}

			if len(obj.Spec.Metrics) > 0 && obj.Spec.Metrics[0].Object != nil && len(obj.Status.CurrentMetrics) > 0 && obj.Status.CurrentMetrics[0].Object != nil {
				assert.Equal(t, obj.Spec.Metrics[0].Object.DescribedObject.APIVersion, obj.Status.CurrentMetrics[0].Object.DescribedObject.APIVersion)
				assert.Equal(t, obj.Spec.Metrics[0].Object.DescribedObject.Kind, obj.Status.CurrentMetrics[0].Object.DescribedObject.Kind)
				assert.Equal(t, obj.Spec.Metrics[0].Object.DescribedObject.Name, obj.Status.CurrentMetrics[0].Object.DescribedObject.Name)
			}

			actualConditions := obj.Status.Conditions
			// TODO: it's ok not to sort these because statusOk
			// contains all the conditions, so we'll never be appending.
			// Default to statusOk when missing any specific conditions
			if tc.expectedConditions == nil {
				tc.expectedConditions = statusOkWithOverrides()
			}
			// clear the message so that we can easily compare
			for i := range actualConditions {
				actualConditions[i].Message = ""
				actualConditions[i].LastTransitionTime = metav1.Time{}
			}
			assert.Equal(t, tc.expectedConditions, actualConditions, "the status conditions should have been as expected")
			tc.statusUpdated = true
			// Every time we reconcile HPA object we are updating status.
			return true, obj, nil
		}()
		if obj != nil {
			tc.processed <- obj.Name
		}
		return handled, obj, err
	})

	fakeScaleClient := &scalefake.FakeScaleClient{}
	fakeScaleClient.AddReactor("get", "replicationcontrollers", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		tc.Lock()
		defer tc.Unlock()

		obj := &autoscalingv1.Scale{
			ObjectMeta: metav1.ObjectMeta{
				Name:      tc.resource.name,
				Namespace: namespace,
			},
			Spec: autoscalingv1.ScaleSpec{
				Replicas: tc.specReplicas,
			},
			Status: autoscalingv1.ScaleStatus{
				Replicas: tc.statusReplicas,
				Selector: selector,
			},
		}
		return true, obj, nil
	})

	fakeScaleClient.AddReactor("get", "deployments", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		tc.Lock()
		defer tc.Unlock()

		obj := &autoscalingv1.Scale{
			ObjectMeta: metav1.ObjectMeta{
				Name:      tc.resource.name,
				Namespace: namespace,
			},
			Spec: autoscalingv1.ScaleSpec{
				Replicas: tc.specReplicas,
			},
			Status: autoscalingv1.ScaleStatus{
				Replicas: tc.statusReplicas,
				Selector: selector,
			},
		}
		return true, obj, nil
	})

	fakeScaleClient.AddReactor("get", "replicasets", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		tc.Lock()
		defer tc.Unlock()

		obj := &autoscalingv1.Scale{
			ObjectMeta: metav1.ObjectMeta{
				Name:      tc.resource.name,
				Namespace: namespace,
			},
			Spec: autoscalingv1.ScaleSpec{
				Replicas: tc.specReplicas,
			},
			Status: autoscalingv1.ScaleStatus{
				Replicas: tc.statusReplicas,
				Selector: selector,
			},
		}
		return true, obj, nil
	})

	fakeScaleClient.AddReactor("update", "replicationcontrollers", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		tc.Lock()
		defer tc.Unlock()

		obj := action.(core.UpdateAction).GetObject().(*autoscalingv1.Scale)
		replicas := action.(core.UpdateAction).GetObject().(*autoscalingv1.Scale).Spec.Replicas
		assert.Equal(t, tc.expectedDesiredReplicas, replicas, "the replica count of the RC should be as expected")
		tc.scaleUpdated = true
		return true, obj, nil
	})

	fakeScaleClient.AddReactor("update", "deployments", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		tc.Lock()
		defer tc.Unlock()

		obj := action.(core.UpdateAction).GetObject().(*autoscalingv1.Scale)
		replicas := action.(core.UpdateAction).GetObject().(*autoscalingv1.Scale).Spec.Replicas
		assert.Equal(t, tc.expectedDesiredReplicas, replicas, "the replica count of the deployment should be as expected")
		tc.scaleUpdated = true
		return true, obj, nil
	})

	fakeScaleClient.AddReactor("update", "replicasets", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		tc.Lock()
		defer tc.Unlock()

		obj := action.(core.UpdateAction).GetObject().(*autoscalingv1.Scale)
		replicas := action.(core.UpdateAction).GetObject().(*autoscalingv1.Scale).Spec.Replicas
		assert.Equal(t, tc.expectedDesiredReplicas, replicas, "the replica count of the replicaset should be as expected")
		tc.scaleUpdated = true
		return true, obj, nil
	})

	fakeWatch := watch.NewFakeWithOptions(watch.FakeOptions{Logger: &logger})
	fakeClient.AddWatchReactor("*", core.DefaultWatchReactor(fakeWatch, nil))

	fakeMetricsClient := &metricsfake.Clientset{}
	fakeMetricsClient.AddReactor("list", "pods", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		tc.Lock()
		defer tc.Unlock()

		metrics := &metricsapi.PodMetricsList{}
		for i, cpu := range tc.reportedLevels {
			// NB: the list reactor actually does label selector filtering for us,
			// so we have to make sure our results match the label selector
			podMetric := metricsapi.PodMetrics{
				ObjectMeta: metav1.ObjectMeta{
					Name:      fmt.Sprintf("%s-%d", podNamePrefix, i),
					Namespace: namespace,
					Labels:    labelSet,
				},
				Timestamp: metav1.Time{Time: time.Now()},
				Window:    metav1.Duration{Duration: time.Minute},
				Containers: []metricsapi.ContainerMetrics{
					{
						Name: "container1",
						Usage: v1.ResourceList{
							v1.ResourceCPU: *resource.NewMilliQuantity(
								int64(cpu/2),
								resource.DecimalSI),
							v1.ResourceMemory: *resource.NewQuantity(
								int64(1024*1024/2),
								resource.BinarySI),
						},
					},
					{
						Name: "container2",
						Usage: v1.ResourceList{
							v1.ResourceCPU: *resource.NewMilliQuantity(
								int64(cpu/2),
								resource.DecimalSI),
							v1.ResourceMemory: *resource.NewQuantity(
								int64(1024*1024/2),
								resource.BinarySI),
						},
					},
				},
			}
			metrics.Items = append(metrics.Items, podMetric)
		}

		return true, metrics, nil
	})

	fakeCMClient := &cmfake.FakeCustomMetricsClient{}
	fakeCMClient.AddReactor("get", "*", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		tc.Lock()
		defer tc.Unlock()

		getForAction, wasGetFor := action.(cmfake.GetForAction)
		if !wasGetFor {
			return true, nil, fmt.Errorf("expected a get-for action, got %v instead", action)
		}

		if getForAction.GetName() == "*" {
			metrics := &cmapi.MetricValueList{}

			// multiple objects
			assert.Equal(t, "pods", getForAction.GetResource().Resource, "the type of object that we requested multiple metrics for should have been pods")
			assert.Equal(t, "qps", getForAction.GetMetricName(), "the metric name requested should have been qps, as specified in the metric spec")

			for i, level := range tc.reportedLevels {
				podMetric := cmapi.MetricValue{
					DescribedObject: v1.ObjectReference{
						Kind:      "Pod",
						Name:      fmt.Sprintf("%s-%d", podNamePrefix, i),
						Namespace: namespace,
					},
					Timestamp: metav1.Time{Time: time.Now()},
					Metric: cmapi.MetricIdentifier{
						Name: "qps",
					},
					Value: *resource.NewMilliQuantity(int64(level), resource.DecimalSI),
				}
				metrics.Items = append(metrics.Items, podMetric)
			}

			return true, metrics, nil
		}

		name := getForAction.GetName()
		mapper := testrestmapper.TestOnlyStaticRESTMapper(legacyscheme.Scheme)
		metrics := &cmapi.MetricValueList{}
		var matchedTarget *autoscalingv2.MetricSpec
		for i, target := range tc.metricsTarget {
			if target.Type == autoscalingv2.ObjectMetricSourceType && name == target.Object.DescribedObject.Name {
				gk := schema.FromAPIVersionAndKind(target.Object.DescribedObject.APIVersion, target.Object.DescribedObject.Kind).GroupKind()
				mapping, err := mapper.RESTMapping(gk)
				if err != nil {
					t.Logf("unable to get mapping for %s: %v", gk.String(), err)
					continue
				}
				groupResource := mapping.Resource.GroupResource()

				if getForAction.GetResource().Resource == groupResource.String() {
					matchedTarget = &tc.metricsTarget[i]
				}
			}
		}
		assert.NotNil(t, matchedTarget, "this request should have matched one of the metric specs")
		assert.Equal(t, "qps", getForAction.GetMetricName(), "the metric name requested should have been qps, as specified in the metric spec")

		metrics.Items = []cmapi.MetricValue{
			{
				DescribedObject: v1.ObjectReference{
					Kind:       matchedTarget.Object.DescribedObject.Kind,
					APIVersion: matchedTarget.Object.DescribedObject.APIVersion,
					Name:       name,
				},
				Timestamp: metav1.Time{Time: time.Now()},
				Metric: cmapi.MetricIdentifier{
					Name: "qps",
				},
				Value: *resource.NewMilliQuantity(int64(tc.reportedLevels[0]), resource.DecimalSI),
			},
		}

		return true, metrics, nil
	})

	fakeEMClient := &emfake.FakeExternalMetricsClient{}

	fakeEMClient.AddReactor("list", "*", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		tc.Lock()
		defer tc.Unlock()

		listAction, wasList := action.(core.ListAction)
		if !wasList {
			return true, nil, fmt.Errorf("expected a list action, got %v instead", action)
		}

		metrics := &emapi.ExternalMetricValueList{}

		assert.Equal(t, "qps", listAction.GetResource().Resource, "the metric name requested should have been qps, as specified in the metric spec")

		for _, level := range tc.reportedLevels {
			metric := emapi.ExternalMetricValue{
				Timestamp:  metav1.Time{Time: time.Now()},
				MetricName: "qps",
				Value:      *resource.NewMilliQuantity(int64(level), resource.DecimalSI),
			}
			metrics.Items = append(metrics.Items, metric)
		}

		return true, metrics, nil
	})

	return fakeClient, fakeMetricsClient, fakeCMClient, fakeEMClient, fakeScaleClient
}

func findCpuUtilization(metricStatus []autoscalingv2.MetricStatus) (utilization *int32) {
	for _, s := range metricStatus {
		if s.Type != autoscalingv2.ResourceMetricSourceType {
			continue
		}
		if s.Resource == nil {
			continue
		}
		if s.Resource.Name != v1.ResourceCPU {
			continue
		}
		if s.Resource.Current.AverageUtilization == nil {
			continue
		}
		return s.Resource.Current.AverageUtilization
	}
	return nil
}

func (tc *testCase) verifyResults(ctx context.Context, t *testing.T) {
	tc.Lock()
	defer tc.Unlock()
	assert.Equal(t, tc.specReplicas != tc.expectedDesiredReplicas, tc.scaleUpdated, "the scale should only be updated if we expected a change in replicas")
	assert.True(t, tc.statusUpdated, "the status should have been updated")
	if tc.verifyEvents {
		assert.Equal(t, tc.specReplicas != tc.expectedDesiredReplicas, tc.eventCreated, "an event should have been created only if we expected a change in replicas")
	}

	tc.verifyRecordedMetric(ctx, t)
}

func (tc *testCase) verifyRecordedMetric(ctx context.Context, t *testing.T) {
	actionStr := string(tc.expectedReportedReconciliationActionLabel)
	errorStr := string(tc.expectedReportedReconciliationErrorLabel)

	if err := wait.PollUntilContextTimeout(ctx, 20*time.Millisecond, 100*time.Millisecond, true, func(ctx context.Context) (done bool, err error) {
		v, err := metricstestutil.GetCounterMetricValue(monitor.ReconciliationsTotal.WithLabelValues(actionStr, errorStr))
		if err != nil {
			return false, nil
		}
		return v >= 1, nil
	}); err != nil {
		t.Fatalf("%s metric was not recorded for action=%s, error=%s", monitor.ReconciliationsTotal.Name, actionStr, errorStr)
	}

	if tc.verifyReconciliationDuration {
		if err := wait.PollUntilContextTimeout(ctx, 20*time.Millisecond, 100*time.Millisecond, true, func(ctx context.Context) (done bool, err error) {
			count, err := metricstestutil.GetHistogramMetricCount(monitor.ReconciliationsDuration.WithLabelValues(actionStr, errorStr))
			if err != nil {
				return false, nil
			}
			return count >= 1, nil
		}); err != nil {
			t.Fatalf("%s metric was not recorded for action=%s, error=%s", monitor.ReconciliationsDuration.Name, actionStr, errorStr)
		}
	}

	if tc.expectedReconciliationCount > 0 {
		v, err := metricstestutil.GetCounterMetricValue(monitor.ReconciliationsTotal.WithLabelValues(actionStr, errorStr))
		if err != nil {
			t.Fatalf("error getting reconciliations total metric: %v", err)
		}
		assert.GreaterOrEqual(t, int(v), tc.expectedReconciliationCount, "reconciliation count should be at least %d", tc.expectedReconciliationCount)

		for metricType, expectedAction := range tc.expectedReportedMetricComputationActionLabels {
			expectedError := tc.expectedReportedMetricComputationErrorLabels[metricType]
			mcv, err := metricstestutil.GetCounterMetricValue(
				monitor.MetricComputationTotal.WithLabelValues(string(expectedAction), string(expectedError), string(metricType)))
			if err != nil {
				t.Fatalf("metric computation total not found for type %s: %v", metricType, err)
			}
			assert.GreaterOrEqual(t, mcv, float64(1), "metric computation count for %s should be at least 1", metricType)

			if tc.verifyMetricComputationDurations {
				count, err := metricstestutil.GetHistogramMetricCount(
					monitor.MetricComputationDuration.WithLabelValues(string(expectedAction), string(expectedError), string(metricType)))
				if err != nil {
					t.Fatalf("error getting metric computation duration for type %s: %v", metricType, err)
				}
				assert.Positive(t, count, "metric computation duration for %s should be recorded", metricType)
			}
		}

		for metricType, expectedCount := range tc.expectedMetricComputationCounts {
			expectedAction := tc.expectedReportedMetricComputationActionLabels[metricType]
			expectedError := tc.expectedReportedMetricComputationErrorLabels[metricType]
			mcv, err := metricstestutil.GetCounterMetricValue(
				monitor.MetricComputationTotal.WithLabelValues(string(expectedAction), string(expectedError), string(metricType)))
			if err != nil {
				t.Fatalf("error getting metric computation count for type %s: %v", metricType, err)
			}
			assert.GreaterOrEqual(t, int(mcv), expectedCount, "metric computation count for %s should be at least %d", metricType, expectedCount)
		}

		// TODO: Retrieve the namespace and HPA names from the test case (tc) to replace hardcoded values below (and check).
		if tc.checkDesiredReplicaMetric {
			v, err := metricstestutil.GetGaugeMetricValue(monitor.DesiredReplicasCount.WithLabelValues("test-namespace", "test-hpa"))
			if err != nil {
				t.Fatalf("error getting desired replicas metric: %v", err)
			}
			assert.InEpsilon(t, float64(tc.expectedDesiredReplicas), v, 0.01,
				"the desired replicas should be recorded in monitor expectedly")
		}
	}
}

func (tc *testCase) setupController(t *testing.T) (*HorizontalController, informers.SharedInformerFactory) {
	testClient, testMetricsClient, testCMClient, testEMClient, testScaleClient := tc.prepareTestClient(t)
	if tc.testClient != nil {
		testClient = tc.testClient
	}
	if tc.testMetricsClient != nil {
		testMetricsClient = tc.testMetricsClient
	}
	if tc.testCMClient != nil {
		testCMClient = tc.testCMClient
	}
	if tc.testEMClient != nil {
		testEMClient = tc.testEMClient
	}
	if tc.testScaleClient != nil {
		testScaleClient = tc.testScaleClient
	}
	metricsClient := metrics.NewRESTMetricsClient(
		testMetricsClient.MetricsV1beta1(),
		testCMClient,
		testEMClient,
	)

	eventClient := &fake.Clientset{}
	eventClient.AddReactor("create", "events", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		tc.Lock()
		defer tc.Unlock()

		obj := action.(core.CreateAction).GetObject().(*v1.Event)
		if tc.verifyEvents {
			switch obj.Reason {
			case "SuccessfulRescale":
				assert.Equal(t, fmt.Sprintf("New size: %d; reason: cpu resource utilization (percentage of request) above target", tc.expectedDesiredReplicas), obj.Message)
			case "DesiredReplicasComputed":
				assert.Equal(t, fmt.Sprintf(
					"Computed the desired num of replicas: %d (avgCPUutil: %d, current replicas: %d)",
					tc.expectedDesiredReplicas,
					(int64(tc.reportedLevels[0])*100)/tc.reportedCPURequests[0].MilliValue(), tc.specReplicas), obj.Message)
			default:
				assert.False(t, true, "Unexpected event: %s / %s", obj.Reason, obj.Message)
			}
		}
		tc.eventCreated = true
		return true, obj, nil
	})

	informerFactory := informers.NewSharedInformerFactory(testClient, controller.NoResyncPeriodFunc())
	defaultDownscalestabilizationWindow := 5 * time.Minute

	tCtx := ktesting.Init(t)
	hpaController := NewHorizontalController(
		tCtx,
		eventClient.CoreV1(),
		testScaleClient,
		testClient.AutoscalingV2(),
		testrestmapper.TestOnlyStaticRESTMapper(legacyscheme.Scheme),
		metricsClient,
		informerFactory.Autoscaling().V2().HorizontalPodAutoscalers(),
		informerFactory.Core().V1().Pods(),
		100*time.Millisecond, // we need non-zero resync period to avoid race conditions
		defaultDownscalestabilizationWindow,
		defaultTestingTolerance,
		defaultTestingCPUInitializationPeriod,
		defaultTestingDelayOfInitialReadinessStatus,
	)
	hpaController.hpaListerSynced = alwaysReady
	if tc.recommendations != nil {
		hpaController.recommendations["test-namespace/test-hpa"] = tc.recommendations
	}
	if tc.hpaSelectors != nil {
		hpaController.hpaSelectors = tc.hpaSelectors
	}

	// reset all HPA prometheus metrics
	monitor.Register()
	monitor.ReconciliationsTotal.Reset()
	monitor.ReconciliationsDuration.Reset()
	monitor.MetricComputationTotal.Reset()
	monitor.MetricComputationDuration.Reset()
	monitor.NumHorizontalPodAutoscalers.Set(0)
	monitor.DesiredReplicasCount.Reset()
	hpaController.monitor = monitor.New()
	return hpaController, informerFactory
}

func hotCPUCreationTime() metav1.Time {
	return metav1.Time{Time: time.Now()}
}

func coolCPUCreationTime() metav1.Time {
	return metav1.Time{Time: time.Now().Add(-3 * time.Minute)}
}

func (tc *testCase) runTestWithController(t *testing.T, hpaController *HorizontalController, informerFactory informers.SharedInformerFactory) {
	ctx, cancel := context.WithCancel(context.Background())
	informerFactory.Start(ctx.Done())

	var wg sync.WaitGroup
	wg.Go(func() {
		hpaController.Run(ctx, 5)
	})
	defer wg.Wait()
	defer cancel()

	tc.Lock()
	shouldWait := tc.verifyEvents
	minReconciliations := tc.expectedReconciliationCount
	tc.Unlock()

	if shouldWait {
		// We need to wait for events to be broadcasted (sleep for longer than record.sleepDuration).
		timeoutTime := time.Now().Add(2 * time.Second)
		for now := time.Now(); timeoutTime.After(now); now = time.Now() {
			sleepUntil := timeoutTime.Sub(now)
			select {
			case <-tc.processed:
				// drain the chan of any sent events to keep it from filling before the timeout
			case <-time.After(sleepUntil):
				// timeout reached, ready to verifyResults
			}
		}
	} else {
		// Wait for HPA to be processed.
		if minReconciliations < 1 {
			t.Logf("minReconciliations should be at least 1, got %d; adjusting to 1", minReconciliations)
			minReconciliations = 1
		}
		timeoutTime := time.Now().Add(5 * time.Second)
		reconciliationsProcessed := 0
		for reconciliationsProcessed < minReconciliations && time.Now().Before(timeoutTime) {
			select {
			case <-tc.processed:
				reconciliationsProcessed++
			case <-time.After(100 * time.Millisecond):
				// continue waiting
			}
		}
		if reconciliationsProcessed < minReconciliations {
			t.Fatalf("expected at least %d reconciliations, but only got %d", minReconciliations, reconciliationsProcessed)
		}
	}

	tc.verifyResults(ctx, t)
}

func (tc *testCase) runTest(t *testing.T) {
	hpaController, informerFactory := tc.setupController(t)
	tc.runTestWithController(t, hpaController, informerFactory)
}

func TestScaleUp(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 5,
		CPUTarget:               30,
		verifyCPUCurrent:        true,
		reportedLevels:          []uint64{300, 500, 700},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:           true,
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
		checkDesiredReplicaMetric: true,
	}
	tc.runTest(t)
}

func TestScaleUpContainer(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 5,
		metricsTarget: []autoscalingv2.MetricSpec{{
			Type: autoscalingv2.ContainerResourceMetricSourceType,
			ContainerResource: &autoscalingv2.ContainerResourceMetricSource{
				Name: v1.ResourceCPU,
				Target: autoscalingv2.MetricTarget{
					Type:               autoscalingv2.UtilizationMetricType,
					AverageUtilization: ptr.To(int32(30)),
				},
				Container: "container1",
			},
		}},
		reportedLevels:      []uint64{300, 500, 700},
		reportedCPURequests: []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:       true,
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ContainerResourceMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ContainerResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleUpUnreadyLessScale(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 4,
		CPUTarget:               30,
		CPUCurrent:              60,
		verifyCPUCurrent:        true,
		reportedLevels:          []uint64{300, 500, 700},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		reportedPodReadiness:    []v1.ConditionStatus{v1.ConditionFalse, v1.ConditionTrue, v1.ConditionTrue},
		useMetricsAPI:           true,
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleUpHotCpuLessScale(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 4,
		CPUTarget:               30,
		CPUCurrent:              60,
		verifyCPUCurrent:        true,
		reportedLevels:          []uint64{300, 500, 700},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		reportedPodStartTime:    []metav1.Time{hotCPUCreationTime(), coolCPUCreationTime(), coolCPUCreationTime()},
		useMetricsAPI:           true,
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleUpUnreadyNoScale(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 3,
		CPUTarget:               30,
		CPUCurrent:              40,
		verifyCPUCurrent:        true,
		reportedLevels:          []uint64{400, 500, 700},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		reportedPodReadiness:    []v1.ConditionStatus{v1.ConditionTrue, v1.ConditionFalse, v1.ConditionFalse},
		useMetricsAPI:           true,
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "ReadyForNewScale",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleUpHotCpuNoScale(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 3,
		CPUTarget:               30,
		CPUCurrent:              40,
		verifyCPUCurrent:        true,
		reportedLevels:          []uint64{400, 500, 700},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		reportedPodReadiness:    []v1.ConditionStatus{v1.ConditionTrue, v1.ConditionFalse, v1.ConditionFalse},
		reportedPodStartTime:    []metav1.Time{coolCPUCreationTime(), hotCPUCreationTime(), hotCPUCreationTime()},
		useMetricsAPI:           true,
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "ReadyForNewScale",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleUpIgnoresFailedPods(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            2,
		statusReplicas:          2,
		expectedDesiredReplicas: 4,
		CPUTarget:               30,
		CPUCurrent:              60,
		verifyCPUCurrent:        true,
		reportedLevels:          []uint64{500, 700},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		reportedPodReadiness:    []v1.ConditionStatus{v1.ConditionTrue, v1.ConditionTrue, v1.ConditionFalse, v1.ConditionFalse},
		reportedPodPhase:        []v1.PodPhase{v1.PodRunning, v1.PodRunning, v1.PodFailed, v1.PodFailed},
		useMetricsAPI:           true,
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleUpIgnoresDeletionPods(t *testing.T) {
	tc := testCase{
		minReplicas:                  2,
		maxReplicas:                  6,
		specReplicas:                 2,
		statusReplicas:               2,
		expectedDesiredReplicas:      4,
		CPUTarget:                    30,
		CPUCurrent:                   60,
		verifyCPUCurrent:             true,
		reportedLevels:               []uint64{500, 700},
		reportedCPURequests:          []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		reportedPodReadiness:         []v1.ConditionStatus{v1.ConditionTrue, v1.ConditionTrue, v1.ConditionFalse, v1.ConditionFalse},
		reportedPodPhase:             []v1.PodPhase{v1.PodRunning, v1.PodRunning, v1.PodRunning, v1.PodRunning},
		reportedPodDeletionTimestamp: []bool{false, false, true, true},
		useMetricsAPI:                true,
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleUpDeployment(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 5,
		CPUTarget:               30,
		verifyCPUCurrent:        true,
		reportedLevels:          []uint64{300, 500, 700},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:           true,
		resource: &fakeResource{
			name:       "test-dep",
			apiVersion: "apps/v1",
			kind:       "Deployment",
		},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleUpReplicaSet(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 5,
		CPUTarget:               30,
		verifyCPUCurrent:        true,
		reportedLevels:          []uint64{300, 500, 700},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:           true,
		resource: &fakeResource{
			name:       "test-replicaset",
			apiVersion: "apps/v1",
			kind:       "ReplicaSet",
		},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleUpCM(t *testing.T) {
	averageValue := resource.MustParse("15.0")
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 4,
		CPUTarget:               0,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.PodsMetricSourceType,
				Pods: &autoscalingv2.PodsMetricSource{
					Metric: autoscalingv2.MetricIdentifier{
						Name: "qps",
					},
					Target: autoscalingv2.MetricTarget{
						Type:         autoscalingv2.AverageValueMetricType,
						AverageValue: &averageValue,
					},
				},
			},
		},
		reportedLevels:      []uint64{20000, 10000, 30000},
		reportedCPURequests: []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.PodsMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.PodsMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleUpCMUnreadyAndHotCpuNoLessScale(t *testing.T) {
	averageValue := resource.MustParse("15.0")
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 6,
		CPUTarget:               0,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.PodsMetricSourceType,
				Pods: &autoscalingv2.PodsMetricSource{
					Metric: autoscalingv2.MetricIdentifier{
						Name: "qps",
					},
					Target: autoscalingv2.MetricTarget{
						Type:         autoscalingv2.AverageValueMetricType,
						AverageValue: &averageValue,
					},
				},
			},
		},
		reportedLevels:                            []uint64{50000, 10000, 30000},
		reportedPodReadiness:                      []v1.ConditionStatus{v1.ConditionTrue, v1.ConditionTrue, v1.ConditionFalse},
		reportedPodStartTime:                      []metav1.Time{coolCPUCreationTime(), coolCPUCreationTime(), hotCPUCreationTime()},
		reportedCPURequests:                       []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.PodsMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.PodsMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleUpCMUnreadyandCpuHot(t *testing.T) {
	averageValue := resource.MustParse("15.0")
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 6,
		CPUTarget:               0,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.PodsMetricSourceType,
				Pods: &autoscalingv2.PodsMetricSource{
					Metric: autoscalingv2.MetricIdentifier{
						Name: "qps",
					},
					Target: autoscalingv2.MetricTarget{
						Type:         autoscalingv2.AverageValueMetricType,
						AverageValue: &averageValue,
					},
				},
			},
		},
		reportedLevels:       []uint64{50000, 15000, 30000},
		reportedPodReadiness: []v1.ConditionStatus{v1.ConditionFalse, v1.ConditionTrue, v1.ConditionFalse},
		reportedPodStartTime: []metav1.Time{hotCPUCreationTime(), coolCPUCreationTime(), hotCPUCreationTime()},
		reportedCPURequests:  []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "SucceededRescale",
		}, autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.ScalingLimited,
			Status: v1.ConditionTrue,
			Reason: "TooManyReplicas",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.PodsMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.PodsMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleUpHotCpuNoScaleWouldScaleDown(t *testing.T) {
	averageValue := resource.MustParse("15.0")
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 6,
		CPUTarget:               0,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.PodsMetricSourceType,
				Pods: &autoscalingv2.PodsMetricSource{
					Metric: autoscalingv2.MetricIdentifier{
						Name: "qps",
					},
					Target: autoscalingv2.MetricTarget{
						Type:         autoscalingv2.AverageValueMetricType,
						AverageValue: &averageValue,
					},
				},
			},
		},
		reportedLevels:       []uint64{50000, 15000, 30000},
		reportedCPURequests:  []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		reportedPodStartTime: []metav1.Time{hotCPUCreationTime(), coolCPUCreationTime(), hotCPUCreationTime()},
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "SucceededRescale",
		}, autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.ScalingLimited,
			Status: v1.ConditionTrue,
			Reason: "TooManyReplicas",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.PodsMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.PodsMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleUpCMObject(t *testing.T) {
	targetValue := resource.MustParse("15.0")
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 4,
		CPUTarget:               0,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.ObjectMetricSourceType,
				Object: &autoscalingv2.ObjectMetricSource{
					DescribedObject: autoscalingv2.CrossVersionObjectReference{
						APIVersion: "apps/v1",
						Kind:       "Deployment",
						Name:       "some-deployment",
					},
					Metric: autoscalingv2.MetricIdentifier{
						Name: "qps",
					},
					Target: autoscalingv2.MetricTarget{
						Type:  autoscalingv2.ValueMetricType,
						Value: &targetValue,
					},
				},
			},
		},
		reportedLevels: []uint64{20000},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ObjectMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ObjectMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleUpFromZeroCMObject(t *testing.T) {
	for _, fgEnabled := range []bool{true, false} {
		t.Run(fmt.Sprintf("HPAScaleToZero=%v", fgEnabled), func(t *testing.T) {
			featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.HPAScaleToZero, fgEnabled)
			targetValue := resource.MustParse("15.0")
			tc := testCase{
				minReplicas:    0,
				maxReplicas:    6,
				specReplicas:   0,
				statusReplicas: 0,
				CPUTarget:      0,
				metricsTarget: []autoscalingv2.MetricSpec{
					{
						Type: autoscalingv2.ObjectMetricSourceType,
						Object: &autoscalingv2.ObjectMetricSource{
							DescribedObject: autoscalingv2.CrossVersionObjectReference{
								APIVersion: "apps/v1",
								Kind:       "Deployment",
								Name:       "some-deployment",
							},
							Metric: autoscalingv2.MetricIdentifier{
								Name: "qps",
							},
							Target: autoscalingv2.MetricTarget{
								Type:  autoscalingv2.ValueMetricType,
								Value: &targetValue,
							},
						},
					},
				},
				reportedLevels: []uint64{20000},
				initialConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
					{
						Type:   autoscalingv2.ScaledToZero,
						Status: v1.ConditionTrue,
						Reason: "ScaledToZero",
					},
				},
			}
			if fgEnabled {
				tc.expectedDesiredReplicas = 2
				tc.expectedConditions = []autoscalingv2.HorizontalPodAutoscalerCondition{
					{Type: autoscalingv2.ScaledToZero, Status: v1.ConditionFalse, Reason: "NotScaledToZero"},
					{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededRescale"},
					{Type: autoscalingv2.ScalingActive, Status: v1.ConditionTrue, Reason: "ValidMetricFound"},
					{Type: autoscalingv2.ScalingLimited, Status: v1.ConditionFalse, Reason: "DesiredWithinRange"},
				}
				tc.expectedReportedReconciliationActionLabel = monitor.ActionLabelScaleUp
				tc.expectedReportedReconciliationErrorLabel = monitor.ErrorLabelNone
				tc.expectedReportedMetricComputationActionLabels = map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
					autoscalingv2.ObjectMetricSourceType: monitor.ActionLabelScaleUp,
				}
				tc.expectedReportedMetricComputationErrorLabels = map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
					autoscalingv2.ObjectMetricSourceType: monitor.ErrorLabelNone,
				}
			} else {
				// FG off: scaledToZeroCondition=false, canScaleFromZero=false → scaling disabled
				tc.expectedDesiredReplicas = 0
				tc.expectedConditions = []autoscalingv2.HorizontalPodAutoscalerCondition{
					{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededGetScale"},
					{Type: autoscalingv2.ScalingActive, Status: v1.ConditionFalse, Reason: "ScalingDisabled"},
				}
				tc.expectedReportedReconciliationActionLabel = monitor.ActionLabelNone
				tc.expectedReportedReconciliationErrorLabel = monitor.ErrorLabelNone
				tc.expectedReportedMetricComputationActionLabels = map[autoscalingv2.MetricSourceType]monitor.ActionLabel{}
				tc.expectedReportedMetricComputationErrorLabels = map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{}
			}
			tc.runTest(t)
		})
	}
}

func TestScaleUpFromZeroIgnoresToleranceCMObject(t *testing.T) {
	for _, fgEnabled := range []bool{true, false} {
		t.Run(fmt.Sprintf("HPAScaleToZero=%v", fgEnabled), func(t *testing.T) {
			featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.HPAScaleToZero, fgEnabled)
			targetValue := resource.MustParse("1.0")
			tc := testCase{
				minReplicas:    0,
				maxReplicas:    6,
				specReplicas:   0,
				statusReplicas: 0,
				CPUTarget:      0,
				metricsTarget: []autoscalingv2.MetricSpec{
					{
						Type: autoscalingv2.ObjectMetricSourceType,
						Object: &autoscalingv2.ObjectMetricSource{
							DescribedObject: autoscalingv2.CrossVersionObjectReference{
								APIVersion: "apps/v1",
								Kind:       "Deployment",
								Name:       "some-deployment",
							},
							Metric: autoscalingv2.MetricIdentifier{
								Name: "qps",
							},
							Target: autoscalingv2.MetricTarget{
								Type:  autoscalingv2.ValueMetricType,
								Value: &targetValue,
							},
						},
					},
				},
				reportedLevels: []uint64{1000},
				initialConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
					{
						Type:   autoscalingv2.ScaledToZero,
						Status: v1.ConditionTrue,
						Reason: "ScaledToZero",
					},
				},
			}
			if fgEnabled {
				tc.expectedDesiredReplicas = 1
				tc.expectedConditions = []autoscalingv2.HorizontalPodAutoscalerCondition{
					{Type: autoscalingv2.ScaledToZero, Status: v1.ConditionFalse, Reason: "NotScaledToZero"},
					{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededRescale"},
					{Type: autoscalingv2.ScalingActive, Status: v1.ConditionTrue, Reason: "ValidMetricFound"},
					{Type: autoscalingv2.ScalingLimited, Status: v1.ConditionFalse, Reason: "DesiredWithinRange"},
				}
				tc.expectedReportedReconciliationActionLabel = monitor.ActionLabelScaleUp
				tc.expectedReportedReconciliationErrorLabel = monitor.ErrorLabelNone
				tc.expectedReportedMetricComputationActionLabels = map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
					autoscalingv2.ObjectMetricSourceType: monitor.ActionLabelScaleUp,
				}
				tc.expectedReportedMetricComputationErrorLabels = map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
					autoscalingv2.ObjectMetricSourceType: monitor.ErrorLabelNone,
				}
			} else {
				// FG off: scaledToZeroCondition=false, canScaleFromZero=false → scaling disabled
				tc.expectedDesiredReplicas = 0
				tc.expectedConditions = []autoscalingv2.HorizontalPodAutoscalerCondition{
					{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededGetScale"},
					{Type: autoscalingv2.ScalingActive, Status: v1.ConditionFalse, Reason: "ScalingDisabled"},
				}
				tc.expectedReportedReconciliationActionLabel = monitor.ActionLabelNone
				tc.expectedReportedReconciliationErrorLabel = monitor.ErrorLabelNone
				tc.expectedReportedMetricComputationActionLabels = map[autoscalingv2.MetricSourceType]monitor.ActionLabel{}
				tc.expectedReportedMetricComputationErrorLabels = map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{}
			}
			tc.runTest(t)
		})
	}
}

func TestScaleUpPerPodCMObject(t *testing.T) {
	targetAverageValue := resource.MustParse("10.0")
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 4,
		CPUTarget:               0,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.ObjectMetricSourceType,
				Object: &autoscalingv2.ObjectMetricSource{
					DescribedObject: autoscalingv2.CrossVersionObjectReference{
						APIVersion: "apps/v1",
						Kind:       "Deployment",
						Name:       "some-deployment",
					},
					Metric: autoscalingv2.MetricIdentifier{
						Name: "qps",
					},
					Target: autoscalingv2.MetricTarget{
						Type:         autoscalingv2.AverageValueMetricType,
						AverageValue: &targetAverageValue,
					},
				},
			},
		},
		reportedLevels: []uint64{40000},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ObjectMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ObjectMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleUpCMExternal(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 4,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.ExternalMetricSourceType,
				External: &autoscalingv2.ExternalMetricSource{
					Metric: autoscalingv2.MetricIdentifier{
						Name:     "qps",
						Selector: &metav1.LabelSelector{},
					},
					Target: autoscalingv2.MetricTarget{
						Type:  autoscalingv2.ValueMetricType,
						Value: resource.NewMilliQuantity(6666, resource.DecimalSI),
					},
				},
			},
		},
		reportedLevels: []uint64{8600},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ExternalMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ExternalMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleUpPerPodCMExternal(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 4,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.ExternalMetricSourceType,
				External: &autoscalingv2.ExternalMetricSource{
					Metric: autoscalingv2.MetricIdentifier{
						Name:     "qps",
						Selector: &metav1.LabelSelector{},
					},
					Target: autoscalingv2.MetricTarget{
						Type:         autoscalingv2.AverageValueMetricType,
						AverageValue: resource.NewMilliQuantity(2222, resource.DecimalSI),
					},
				},
			},
		},
		reportedLevels: []uint64{8600},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ExternalMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ExternalMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleDown(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            5,
		statusReplicas:          5,
		expectedDesiredReplicas: 3,
		CPUTarget:               50,
		verifyCPUCurrent:        true,
		reportedLevels:          []uint64{100, 300, 500, 250, 250},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:           true,
		recommendations:         []timestampedRecommendation{},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleDownContainerResource(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            5,
		statusReplicas:          5,
		expectedDesiredReplicas: 3,
		reportedLevels:          []uint64{100, 300, 500, 250, 250},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		metricsTarget: []autoscalingv2.MetricSpec{{
			Type: autoscalingv2.ContainerResourceMetricSourceType,
			ContainerResource: &autoscalingv2.ContainerResourceMetricSource{
				Container: "container2",
				Name:      v1.ResourceCPU,
				Target: autoscalingv2.MetricTarget{
					Type:               autoscalingv2.UtilizationMetricType,
					AverageUtilization: ptr.To(int32(50)),
				},
			},
		}},
		useMetricsAPI:   true,
		recommendations: []timestampedRecommendation{},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ContainerResourceMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ContainerResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleDownWithScalingRules(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		scaleUpRules:            generateScalingRules(0, 0, 100, 15, 30),
		specReplicas:            5,
		statusReplicas:          5,
		expectedDesiredReplicas: 3,
		CPUTarget:               50,
		verifyCPUCurrent:        true,
		reportedLevels:          []uint64{100, 300, 500, 250, 250},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:           true,
		recommendations:         []timestampedRecommendation{},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleUpOneMetricInvalid(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 4,
		CPUTarget:               30,
		verifyCPUCurrent:        true,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: "CheddarCheese",
			},
		},
		reportedLevels:      []uint64{300, 400, 500},
		reportedCPURequests: []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelInternal,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
			// Actually, such an invalid type should be validated in the kube-apiserver and invalid metric type shouldn't be recorded.
			"CheddarCheese": monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
			// Actually, such an invalid type should be validated in the kube-apiserver and invalid metric type shouldn't be recorded.
			"CheddarCheese": monitor.ErrorLabelSpec,
		},
	}
	tc.runTest(t)
}

func TestScaleUpFromZeroOneMetricInvalid(t *testing.T) {
	for _, fgEnabled := range []bool{true, false} {
		t.Run(fmt.Sprintf("HPAScaleToZero=%v", fgEnabled), func(t *testing.T) {
			featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.HPAScaleToZero, fgEnabled)
			// This test uses CPU metrics, not object/external, so it can't scale from zero
			// regardless of feature gate state (only object/external metrics support scale-from-zero per KEP-2021)
			tc := testCase{
				minReplicas:             0,
				maxReplicas:             6,
				specReplicas:            0,
				statusReplicas:          0,
				expectedDesiredReplicas: 0,
				CPUTarget:               30,
				verifyCPUCurrent:        false,
				metricsTarget: []autoscalingv2.MetricSpec{
					{
						Type: "CheddarCheese",
					},
				},
				reportedLevels:      []uint64{300, 400, 500},
				reportedCPURequests: []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
				recommendations:     []timestampedRecommendation{},
				expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
					{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededGetScale"},
					{Type: autoscalingv2.ScalingActive, Status: v1.ConditionFalse, Reason: "ScalingDisabled"},
				},
				expectedReportedReconciliationActionLabel:     monitor.ActionLabelNone,
				expectedReportedReconciliationErrorLabel:      monitor.ErrorLabelNone,
				expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{},
				expectedReportedMetricComputationErrorLabels:  map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{},
			}
			tc.runTest(t)
		})
	}
}

func TestScaleUpBothMetricsEmpty(t *testing.T) { // Switch to missing
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 3,
		CPUTarget:               0,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: "CheddarCheese",
			},
		},
		reportedLevels:      []uint64{},
		reportedCPURequests: []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
			{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededGetScale"},
			{Type: autoscalingv2.ScalingActive, Status: v1.ConditionFalse, Reason: "InvalidMetricSourceType"},
		},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelInternal,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			// Actually, such an invalid type should be validated in the kube-apiserver and invalid metric type shouldn't be recorded.
			"CheddarCheese": monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			// Actually, such an invalid type should be validated in the kube-apiserver and invalid metric type shouldn't be recorded.
			"CheddarCheese": monitor.ErrorLabelSpec,
		},
	}
	tc.runTest(t)
}

func TestScaleDownStabilizeInitialSize(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            5,
		statusReplicas:          5,
		expectedDesiredReplicas: 5,
		CPUTarget:               50,
		verifyCPUCurrent:        true,
		reportedLevels:          []uint64{100, 300, 500, 250, 250},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:           true,
		recommendations:         nil,
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "ReadyForNewScale",
		}, autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "ScaleDownStabilized",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleDownCM(t *testing.T) {
	averageValue := resource.MustParse("20.0")
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            5,
		statusReplicas:          5,
		expectedDesiredReplicas: 3,
		CPUTarget:               0,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.PodsMetricSourceType,
				Pods: &autoscalingv2.PodsMetricSource{
					Metric: autoscalingv2.MetricIdentifier{
						Name: "qps",
					},
					Target: autoscalingv2.MetricTarget{
						Type:         autoscalingv2.AverageValueMetricType,
						AverageValue: &averageValue,
					},
				},
			},
		},
		reportedLevels:      []uint64{12000, 12000, 12000, 12000, 12000},
		reportedCPURequests: []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		recommendations:     []timestampedRecommendation{},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.PodsMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.PodsMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleDownCMObject(t *testing.T) {
	targetValue := resource.MustParse("20.0")
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            5,
		statusReplicas:          5,
		expectedDesiredReplicas: 3,
		CPUTarget:               0,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.ObjectMetricSourceType,
				Object: &autoscalingv2.ObjectMetricSource{
					DescribedObject: autoscalingv2.CrossVersionObjectReference{
						APIVersion: "apps/v1",
						Kind:       "Deployment",
						Name:       "some-deployment",
					},
					Metric: autoscalingv2.MetricIdentifier{
						Name: "qps",
					},
					Target: autoscalingv2.MetricTarget{
						Type:  autoscalingv2.ValueMetricType,
						Value: &targetValue,
					},
				},
			},
		},
		reportedLevels:      []uint64{12000},
		reportedCPURequests: []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		recommendations:     []timestampedRecommendation{},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ObjectMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ObjectMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleDownToZeroCMObject(t *testing.T) {
	for _, fgEnabled := range []bool{true, false} {
		t.Run(fmt.Sprintf("HPAScaleToZero=%v", fgEnabled), func(t *testing.T) {
			featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.HPAScaleToZero, fgEnabled)
			targetValue := resource.MustParse("20.0")
			tc := testCase{
				minReplicas:             0,
				maxReplicas:             6,
				specReplicas:            5,
				statusReplicas:          5,
				expectedDesiredReplicas: 0,
				CPUTarget:               0,
				metricsTarget: []autoscalingv2.MetricSpec{
					{
						Type: autoscalingv2.ObjectMetricSourceType,
						Object: &autoscalingv2.ObjectMetricSource{
							DescribedObject: autoscalingv2.CrossVersionObjectReference{
								APIVersion: "apps/v1",
								Kind:       "Deployment",
								Name:       "some-deployment",
							},
							Metric: autoscalingv2.MetricIdentifier{
								Name: "qps",
							},
							Target: autoscalingv2.MetricTarget{
								Type:  autoscalingv2.ValueMetricType,
								Value: &targetValue,
							},
						},
					},
				},
				reportedLevels:      []uint64{0},
				reportedCPURequests: []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
				recommendations:     []timestampedRecommendation{},
				expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
				expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
				expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
					autoscalingv2.ObjectMetricSourceType: monitor.ActionLabelScaleDown,
				},
				expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
					autoscalingv2.ObjectMetricSourceType: monitor.ErrorLabelNone,
				},
			}
			if fgEnabled {
				// FG on: ScaledToZero condition set on scale-down to zero
				tc.expectedConditions = statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
					Type:   autoscalingv2.ScaledToZero,
					Status: v1.ConditionTrue,
					Reason: "ScaledToZero",
				})
			} else {
				// FG off: no ScaledToZero condition, but scale-down still happens
				tc.expectedConditions = statusOkWithOverrides()
			}
			tc.runTest(t)
		})
	}
}

func TestScaleDownPerPodCMObject(t *testing.T) {
	targetAverageValue := resource.MustParse("20.0")
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            5,
		statusReplicas:          5,
		expectedDesiredReplicas: 3,
		CPUTarget:               0,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.ObjectMetricSourceType,
				Object: &autoscalingv2.ObjectMetricSource{
					DescribedObject: autoscalingv2.CrossVersionObjectReference{
						APIVersion: "apps/v1",
						Kind:       "Deployment",
						Name:       "some-deployment",
					},
					Metric: autoscalingv2.MetricIdentifier{
						Name: "qps",
					},
					Target: autoscalingv2.MetricTarget{
						Type:         autoscalingv2.AverageValueMetricType,
						AverageValue: &targetAverageValue,
					},
				},
			},
		},
		reportedLevels:      []uint64{60000},
		reportedCPURequests: []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		recommendations:     []timestampedRecommendation{},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ObjectMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ObjectMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleDownCMExternal(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            5,
		statusReplicas:          5,
		expectedDesiredReplicas: 3,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.ExternalMetricSourceType,
				External: &autoscalingv2.ExternalMetricSource{
					Metric: autoscalingv2.MetricIdentifier{
						Name:     "qps",
						Selector: &metav1.LabelSelector{},
					},
					Target: autoscalingv2.MetricTarget{
						Type:  autoscalingv2.ValueMetricType,
						Value: resource.NewMilliQuantity(14400, resource.DecimalSI),
					},
				},
			},
		},
		reportedLevels:  []uint64{8600},
		recommendations: []timestampedRecommendation{},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ExternalMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ExternalMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleDownToZeroCMExternal(t *testing.T) {
	for _, fgEnabled := range []bool{true, false} {
		t.Run(fmt.Sprintf("HPAScaleToZero=%v", fgEnabled), func(t *testing.T) {
			featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.HPAScaleToZero, fgEnabled)
			tc := testCase{
				minReplicas:             0,
				maxReplicas:             6,
				specReplicas:            5,
				statusReplicas:          5,
				expectedDesiredReplicas: 0,
				metricsTarget: []autoscalingv2.MetricSpec{
					{
						Type: autoscalingv2.ExternalMetricSourceType,
						External: &autoscalingv2.ExternalMetricSource{
							Metric: autoscalingv2.MetricIdentifier{
								Name:     "qps",
								Selector: &metav1.LabelSelector{},
							},
							Target: autoscalingv2.MetricTarget{
								Type:  autoscalingv2.ValueMetricType,
								Value: resource.NewMilliQuantity(14400, resource.DecimalSI),
							},
						},
					},
				},
				reportedLevels:  []uint64{0},
				recommendations: []timestampedRecommendation{},
				expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
				expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
				expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
					autoscalingv2.ExternalMetricSourceType: monitor.ActionLabelScaleDown,
				},
				expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
					autoscalingv2.ExternalMetricSourceType: monitor.ErrorLabelNone,
				},
			}
			if fgEnabled {
				tc.expectedConditions = statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
					Type:   autoscalingv2.ScaledToZero,
					Status: v1.ConditionTrue,
					Reason: "ScaledToZero",
				})
			} else {
				tc.expectedConditions = statusOkWithOverrides()
			}
			tc.runTest(t)
		})
	}
}

func TestScaleUpFromZeroWithoutCondition(t *testing.T) {
	for _, fgEnabled := range []bool{true, false} {
		t.Run(fmt.Sprintf("HPAScaleToZero=%v", fgEnabled), func(t *testing.T) {
			featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.HPAScaleToZero, fgEnabled)
			// Without ScaledToZero condition, scaling from zero is disabled regardless of feature gate
			targetValue := resource.MustParse("15.0")
			tc := testCase{
				minReplicas:             0,
				maxReplicas:             6,
				specReplicas:            0,
				statusReplicas:          0,
				expectedDesiredReplicas: 0,
				CPUTarget:               0,
				metricsTarget: []autoscalingv2.MetricSpec{
					{
						Type: autoscalingv2.ObjectMetricSourceType,
						Object: &autoscalingv2.ObjectMetricSource{
							DescribedObject: autoscalingv2.CrossVersionObjectReference{
								APIVersion: "apps/v1",
								Kind:       "Deployment",
								Name:       "some-deployment",
							},
							Metric: autoscalingv2.MetricIdentifier{
								Name: "qps",
							},
							Target: autoscalingv2.MetricTarget{
								Type:  autoscalingv2.ValueMetricType,
								Value: &targetValue,
							},
						},
					},
				},
				reportedLevels: []uint64{20000},
				expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
					{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededGetScale"},
					{Type: autoscalingv2.ScalingActive, Status: v1.ConditionFalse, Reason: "ScalingDisabled"},
				},
				expectedReportedReconciliationActionLabel:     monitor.ActionLabelNone,
				expectedReportedReconciliationErrorLabel:      monitor.ErrorLabelNone,
				expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{},
				expectedReportedMetricComputationErrorLabels:  map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{},
			}
			tc.runTest(t)
		})
	}
}

func TestScaleUpFromZeroWhenMinReplicasIncreased(t *testing.T) {
	for _, fgEnabled := range []bool{true, false} {
		t.Run(fmt.Sprintf("HPAScaleToZero=%v", fgEnabled), func(t *testing.T) {
			featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.HPAScaleToZero, fgEnabled)
			tc := testCase{
				minReplicas:    2,
				maxReplicas:    6,
				specReplicas:   0,
				statusReplicas: 0,
				CPUTarget:      0,
				metricsTarget: []autoscalingv2.MetricSpec{
					{
						Type: autoscalingv2.ObjectMetricSourceType,
						Object: &autoscalingv2.ObjectMetricSource{
							DescribedObject: autoscalingv2.CrossVersionObjectReference{
								APIVersion: "apps/v1",
								Kind:       "Deployment",
								Name:       "some-deployment",
							},
							Metric: autoscalingv2.MetricIdentifier{
								Name: "qps",
							},
							Target: autoscalingv2.MetricTarget{
								Type:  autoscalingv2.ValueMetricType,
								Value: resource.NewMilliQuantity(15000, resource.DecimalSI),
							},
						},
					},
				},
				reportedLevels: []uint64{10000},
				initialConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
					{
						Type:   autoscalingv2.ScaledToZero,
						Status: v1.ConditionTrue,
						Reason: "ScaledToZero",
					},
				},
			}
			if fgEnabled {
				// HPA previously scaled to zero, minReplicas increased to 2 → scale up to minReplicas
				tc.expectedDesiredReplicas = 2
				tc.expectedConditions = []autoscalingv2.HorizontalPodAutoscalerCondition{
					{Type: autoscalingv2.ScaledToZero, Status: v1.ConditionFalse, Reason: "NotScaledToZero"},
					{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededRescale"},
					{Type: autoscalingv2.ScalingActive, Status: v1.ConditionTrue, Reason: "ValidMetricFound"},
					{Type: autoscalingv2.ScalingLimited, Status: v1.ConditionTrue, Reason: "TooFewReplicas"},
				}
				tc.expectedReportedReconciliationActionLabel = monitor.ActionLabelScaleUp
				tc.expectedReportedReconciliationErrorLabel = monitor.ErrorLabelNone
				tc.expectedReportedMetricComputationActionLabels = map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
					autoscalingv2.ObjectMetricSourceType: monitor.ActionLabelScaleUp,
				}
				tc.expectedReportedMetricComputationErrorLabels = map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
					autoscalingv2.ObjectMetricSourceType: monitor.ErrorLabelNone,
				}
			} else {
				// FG off: scaledToZeroCondition=false → treated as manual scale-down, scaling disabled
				tc.expectedDesiredReplicas = 0
				tc.expectedConditions = []autoscalingv2.HorizontalPodAutoscalerCondition{
					{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededGetScale"},
					{Type: autoscalingv2.ScalingActive, Status: v1.ConditionFalse, Reason: "ScalingDisabled"},
				}
				tc.expectedReportedReconciliationActionLabel = monitor.ActionLabelNone
				tc.expectedReportedReconciliationErrorLabel = monitor.ErrorLabelNone
				tc.expectedReportedMetricComputationActionLabels = map[autoscalingv2.MetricSourceType]monitor.ActionLabel{}
				tc.expectedReportedMetricComputationErrorLabels = map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{}
			}
			tc.runTest(t)
		})
	}
}

func TestScaledToZeroConditionHandledOnNormalRescale(t *testing.T) {
	for _, fgEnabled := range []bool{true, false} {
		t.Run(fmt.Sprintf("HPAScaleToZero=%v", fgEnabled), func(t *testing.T) {
			featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.HPAScaleToZero, fgEnabled)
			tc := testCase{
				minReplicas:             1,
				maxReplicas:             6,
				specReplicas:            3,
				statusReplicas:          3,
				expectedDesiredReplicas: 5,
				CPUTarget:               30,
				reportedLevels:          []uint64{300, 500, 700},
				reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
				useMetricsAPI:           true,
				initialConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
					{
						Type:   autoscalingv2.ScaledToZero,
						Status: v1.ConditionTrue,
						Reason: "ScaledToZero",
					},
				},
				expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
				expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
				expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
					autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
				},
				expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
					autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
				},
			}
			if fgEnabled {
				// FG on: ScaledToZero condition set to False on rescale
				tc.expectedConditions = []autoscalingv2.HorizontalPodAutoscalerCondition{
					{Type: autoscalingv2.ScaledToZero, Status: v1.ConditionFalse, Reason: "NotScaledToZero"},
					{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededRescale"},
					{Type: autoscalingv2.ScalingActive, Status: v1.ConditionTrue, Reason: "ValidMetricFound"},
					{Type: autoscalingv2.ScalingLimited, Status: v1.ConditionFalse, Reason: "DesiredWithinRange"},
				}
			} else {
				// FG off: stale ScaledToZero condition removed on rescale
				tc.expectedConditions = statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
					Type: autoscalingv2.ScalingLimited, Status: v1.ConditionFalse,
					Reason: "DesiredWithinRange",
				})
			}
			tc.runTest(t)
		})
	}
}

func TestManualScaleToZeroDisablesHPA(t *testing.T) {
	for _, fgEnabled := range []bool{true, false} {
		t.Run(fmt.Sprintf("HPAScaleToZero=%v", fgEnabled), func(t *testing.T) {
			// With minReplicas >= 1, a workload manually scaled to zero (no ScaledToZero condition)
			// should cause HPA to pause (ScalingDisabled), regardless of feature gate
			featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.HPAScaleToZero, fgEnabled)
			tc := testCase{
				minReplicas:             1,
				maxReplicas:             6,
				specReplicas:            0,
				statusReplicas:          0,
				expectedDesiredReplicas: 0,
				CPUTarget:               50,
				reportedLevels:          []uint64{},
				reportedCPURequests:     []resource.Quantity{},
				useMetricsAPI:           true,
				expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
					{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededGetScale"},
					{Type: autoscalingv2.ScalingActive, Status: v1.ConditionFalse, Reason: "ScalingDisabled"},
				},
				expectedReportedReconciliationActionLabel:     monitor.ActionLabelNone,
				expectedReportedReconciliationErrorLabel:      monitor.ErrorLabelNone,
				expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{},
				expectedReportedMetricComputationErrorLabels:  map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{},
			}
			tc.runTest(t)
		})
	}
}

func TestScaleDownPerPodCMExternal(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            5,
		statusReplicas:          5,
		expectedDesiredReplicas: 3,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.ExternalMetricSourceType,
				External: &autoscalingv2.ExternalMetricSource{
					Metric: autoscalingv2.MetricIdentifier{
						Name:     "qps",
						Selector: &metav1.LabelSelector{},
					},
					Target: autoscalingv2.MetricTarget{
						Type:         autoscalingv2.AverageValueMetricType,
						AverageValue: resource.NewMilliQuantity(3000, resource.DecimalSI),
					},
				},
			},
		},
		reportedLevels:  []uint64{8600},
		recommendations: []timestampedRecommendation{},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ExternalMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ExternalMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleDownIncludeUnreadyPods(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            5,
		statusReplicas:          5,
		expectedDesiredReplicas: 2,
		CPUTarget:               50,
		CPUCurrent:              30,
		verifyCPUCurrent:        true,
		reportedLevels:          []uint64{100, 300, 500, 250, 250},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:           true,
		reportedPodReadiness:    []v1.ConditionStatus{v1.ConditionTrue, v1.ConditionTrue, v1.ConditionTrue, v1.ConditionFalse, v1.ConditionFalse},
		recommendations:         []timestampedRecommendation{},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleDownIgnoreHotCpuPods(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            5,
		statusReplicas:          5,
		expectedDesiredReplicas: 2,
		CPUTarget:               50,
		CPUCurrent:              30,
		verifyCPUCurrent:        true,
		reportedLevels:          []uint64{100, 300, 500, 250, 250},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:           true,
		reportedPodStartTime:    []metav1.Time{coolCPUCreationTime(), coolCPUCreationTime(), coolCPUCreationTime(), hotCPUCreationTime(), hotCPUCreationTime()},
		recommendations:         []timestampedRecommendation{},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleDownIgnoresFailedPods(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            5,
		statusReplicas:          5,
		expectedDesiredReplicas: 3,
		CPUTarget:               50,
		CPUCurrent:              28,
		verifyCPUCurrent:        true,
		reportedLevels:          []uint64{100, 300, 500, 250, 250},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:           true,
		reportedPodReadiness:    []v1.ConditionStatus{v1.ConditionTrue, v1.ConditionTrue, v1.ConditionTrue, v1.ConditionTrue, v1.ConditionTrue, v1.ConditionFalse, v1.ConditionFalse},
		reportedPodPhase:        []v1.PodPhase{v1.PodRunning, v1.PodRunning, v1.PodRunning, v1.PodRunning, v1.PodRunning, v1.PodFailed, v1.PodFailed},
		recommendations:         []timestampedRecommendation{},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestScaleDownIgnoresDeletionPods(t *testing.T) {
	tc := testCase{
		minReplicas:                  2,
		maxReplicas:                  6,
		specReplicas:                 5,
		statusReplicas:               5,
		expectedDesiredReplicas:      3,
		CPUTarget:                    50,
		CPUCurrent:                   28,
		verifyCPUCurrent:             true,
		reportedLevels:               []uint64{100, 300, 500, 250, 250},
		reportedCPURequests:          []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:                true,
		reportedPodReadiness:         []v1.ConditionStatus{v1.ConditionTrue, v1.ConditionTrue, v1.ConditionTrue, v1.ConditionTrue, v1.ConditionTrue, v1.ConditionFalse, v1.ConditionFalse},
		reportedPodPhase:             []v1.PodPhase{v1.PodRunning, v1.PodRunning, v1.PodRunning, v1.PodRunning, v1.PodRunning, v1.PodRunning, v1.PodRunning},
		reportedPodDeletionTimestamp: []bool{false, false, false, false, false, true, true},
		recommendations:              []timestampedRecommendation{},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestTolerance(t *testing.T) {
	tc := testCase{
		minReplicas:             1,
		maxReplicas:             5,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 3,
		CPUTarget:               100,
		reportedLevels:          []uint64{1010, 1030, 1020},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("0.9"), resource.MustParse("1.0"), resource.MustParse("1.1")},
		useMetricsAPI:           true,
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "ReadyForNewScale",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestConfigurableTolerance(t *testing.T) {
	onePercentQuantity := resource.MustParse("0.01")
	ninetyPercentQuantity := resource.MustParse("0.9")

	testCases := []struct {
		name                      string
		configurableToleranceGate bool
		replicas                  int32
		scaleUpRules              *autoscalingv2.HPAScalingRules
		scaleDownRules            *autoscalingv2.HPAScalingRules
		reportedLevels            []uint64
		reportedCPURequests       []resource.Quantity
		expectedDesiredReplicas   int32
		expectedConditionReason   string
		expectedActionLabel       monitor.ActionLabel
	}{
		{
			name:                      "Scaling up because of a 1% configurable tolerance",
			configurableToleranceGate: true,
			replicas:                  3,
			scaleUpRules: &autoscalingv2.HPAScalingRules{
				Tolerance: &onePercentQuantity,
			},
			reportedLevels:          []uint64{1010, 1030, 1020},
			reportedCPURequests:     []resource.Quantity{resource.MustParse("0.9"), resource.MustParse("1.0"), resource.MustParse("1.1")},
			expectedDesiredReplicas: 4,
			expectedConditionReason: "SucceededRescale",
			expectedActionLabel:     monitor.ActionLabelScaleUp,
		},
		{
			name:                      "No scale-down because of a 90% configurable tolerance",
			configurableToleranceGate: true,
			replicas:                  3,
			scaleDownRules: &autoscalingv2.HPAScalingRules{
				Tolerance: &ninetyPercentQuantity,
			},
			reportedLevels:          []uint64{300, 300, 300},
			reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
			expectedDesiredReplicas: 3,
			expectedConditionReason: "ReadyForNewScale",
			expectedActionLabel:     monitor.ActionLabelNone,
		},
		{
			name:                      "No scaling because of the large default tolerance",
			configurableToleranceGate: true,
			replicas:                  3,
			reportedLevels:            []uint64{1010, 1030, 1020},
			reportedCPURequests:       []resource.Quantity{resource.MustParse("0.9"), resource.MustParse("1.0"), resource.MustParse("1.1")},
			expectedDesiredReplicas:   3,
			expectedConditionReason:   "ReadyForNewScale",
			expectedActionLabel:       monitor.ActionLabelNone,
		},
		{
			name:                      "No scaling because the configurable tolerance is ignored as the feature gate is disabled",
			configurableToleranceGate: false,
			replicas:                  3,
			scaleUpRules: &autoscalingv2.HPAScalingRules{
				Tolerance: &onePercentQuantity,
			},
			reportedLevels:          []uint64{1010, 1030, 1020},
			reportedCPURequests:     []resource.Quantity{resource.MustParse("0.9"), resource.MustParse("1.0"), resource.MustParse("1.1")},
			expectedDesiredReplicas: 3,
			expectedConditionReason: "ReadyForNewScale",
			expectedActionLabel:     monitor.ActionLabelNone,
		},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.HPAConfigurableTolerance, tc.configurableToleranceGate)
			tc := testCase{
				minReplicas:             1,
				maxReplicas:             5,
				specReplicas:            tc.replicas,
				statusReplicas:          tc.replicas,
				scaleDownRules:          tc.scaleDownRules,
				scaleUpRules:            tc.scaleUpRules,
				expectedDesiredReplicas: tc.expectedDesiredReplicas,
				CPUTarget:               100,
				reportedLevels:          tc.reportedLevels,
				reportedCPURequests:     tc.reportedCPURequests,
				useMetricsAPI:           true,
				expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
					Type:   autoscalingv2.AbleToScale,
					Status: v1.ConditionTrue,
					Reason: tc.expectedConditionReason,
				}),
				expectedReportedReconciliationActionLabel: tc.expectedActionLabel,
				expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
				expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
					autoscalingv2.ResourceMetricSourceType: tc.expectedActionLabel,
				},
				expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
					autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
				},
			}
			tc.runTest(t)
		})
	}
}

func TestToleranceCM(t *testing.T) {
	averageValue := resource.MustParse("20.0")
	tc := testCase{
		minReplicas:             1,
		maxReplicas:             5,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 3,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.PodsMetricSourceType,
				Pods: &autoscalingv2.PodsMetricSource{
					Metric: autoscalingv2.MetricIdentifier{
						Name: "qps",
					},
					Target: autoscalingv2.MetricTarget{
						Type:         autoscalingv2.AverageValueMetricType,
						AverageValue: &averageValue,
					},
				},
			},
		},
		reportedLevels:      []uint64{20000, 20001, 21000},
		reportedCPURequests: []resource.Quantity{resource.MustParse("0.9"), resource.MustParse("1.0"), resource.MustParse("1.1")},
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "ReadyForNewScale",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.PodsMetricSourceType: monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.PodsMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestToleranceCMObject(t *testing.T) {
	targetValue := resource.MustParse("20.0")
	tc := testCase{
		minReplicas:             1,
		maxReplicas:             5,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 3,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.ObjectMetricSourceType,
				Object: &autoscalingv2.ObjectMetricSource{
					DescribedObject: autoscalingv2.CrossVersionObjectReference{
						APIVersion: "apps/v1",
						Kind:       "Deployment",
						Name:       "some-deployment",
					},
					Metric: autoscalingv2.MetricIdentifier{
						Name: "qps",
					},
					Target: autoscalingv2.MetricTarget{
						Type:  autoscalingv2.ValueMetricType,
						Value: &targetValue,
					},
				},
			},
		},
		reportedLevels:      []uint64{20050},
		reportedCPURequests: []resource.Quantity{resource.MustParse("0.9"), resource.MustParse("1.0"), resource.MustParse("1.1")},
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "ReadyForNewScale",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ObjectMetricSourceType: monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ObjectMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestToleranceCMExternal(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            4,
		statusReplicas:          4,
		expectedDesiredReplicas: 4,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.ExternalMetricSourceType,
				External: &autoscalingv2.ExternalMetricSource{
					Metric: autoscalingv2.MetricIdentifier{
						Name:     "qps",
						Selector: &metav1.LabelSelector{},
					},
					Target: autoscalingv2.MetricTarget{
						Type:  autoscalingv2.ValueMetricType,
						Value: resource.NewMilliQuantity(8666, resource.DecimalSI),
					},
				},
			},
		},
		reportedLevels: []uint64{8600},
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "ReadyForNewScale",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ExternalMetricSourceType: monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ExternalMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestTolerancePerPodCMObject(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            4,
		statusReplicas:          4,
		expectedDesiredReplicas: 4,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.ObjectMetricSourceType,
				Object: &autoscalingv2.ObjectMetricSource{
					DescribedObject: autoscalingv2.CrossVersionObjectReference{
						APIVersion: "apps/v1",
						Kind:       "Deployment",
						Name:       "some-deployment",
					},
					Metric: autoscalingv2.MetricIdentifier{
						Name:     "qps",
						Selector: &metav1.LabelSelector{},
					},
					Target: autoscalingv2.MetricTarget{
						Type:         autoscalingv2.AverageValueMetricType,
						AverageValue: resource.NewMilliQuantity(2200, resource.DecimalSI),
					},
				},
			},
		},
		reportedLevels: []uint64{8600},
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "ReadyForNewScale",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ObjectMetricSourceType: monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ObjectMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestTolerancePerPodCMExternal(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            4,
		statusReplicas:          4,
		expectedDesiredReplicas: 4,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.ExternalMetricSourceType,
				External: &autoscalingv2.ExternalMetricSource{
					Metric: autoscalingv2.MetricIdentifier{
						Name:     "qps",
						Selector: &metav1.LabelSelector{},
					},
					Target: autoscalingv2.MetricTarget{
						Type:         autoscalingv2.AverageValueMetricType,
						AverageValue: resource.NewMilliQuantity(2200, resource.DecimalSI),
					},
				},
			},
		},
		reportedLevels: []uint64{8600},
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "ReadyForNewScale",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ExternalMetricSourceType: monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ExternalMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestMinReplicas(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             5,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 2,
		CPUTarget:               90,
		reportedLevels:          []uint64{10, 95, 10},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("0.9"), resource.MustParse("1.0"), resource.MustParse("1.1")},
		useMetricsAPI:           true,
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.ScalingLimited,
			Status: v1.ConditionTrue,
			Reason: "TooFewReplicas",
		}),
		recommendations: []timestampedRecommendation{},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestZeroMinReplicasDesiredZero(t *testing.T) {
	tc := testCase{
		minReplicas:             0,
		maxReplicas:             5,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 0,
		CPUTarget:               90,
		reportedLevels:          []uint64{0, 0, 0},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("0.9"), resource.MustParse("1.0"), resource.MustParse("1.1")},
		useMetricsAPI:           true,
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.ScalingLimited,
			Status: v1.ConditionFalse,
			Reason: "DesiredWithinRange",
		}),
		recommendations: []timestampedRecommendation{},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestMinReplicasDesiredZero(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             5,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 2,
		CPUTarget:               90,
		reportedLevels:          []uint64{0, 0, 0},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("0.9"), resource.MustParse("1.0"), resource.MustParse("1.1")},
		useMetricsAPI:           true,
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.ScalingLimited,
			Status: v1.ConditionTrue,
			Reason: "TooFewReplicas",
		}),
		recommendations: []timestampedRecommendation{},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestZeroReplicas(t *testing.T) {
	tc := testCase{
		minReplicas:             3,
		maxReplicas:             5,
		specReplicas:            0,
		statusReplicas:          0,
		expectedDesiredReplicas: 0,
		CPUTarget:               90,
		reportedLevels:          []uint64{},
		reportedCPURequests:     []resource.Quantity{},
		useMetricsAPI:           true,
		expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
			{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededGetScale"},
			{Type: autoscalingv2.ScalingActive, Status: v1.ConditionFalse, Reason: "ScalingDisabled"},
		},
		expectedReportedReconciliationActionLabel:     monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:      monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{},
		expectedReportedMetricComputationErrorLabels:  map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{},
	}
	tc.runTest(t)
}

func TestTooFewReplicas(t *testing.T) {
	tc := testCase{
		minReplicas:             3,
		maxReplicas:             5,
		specReplicas:            2,
		statusReplicas:          2,
		expectedDesiredReplicas: 3,
		CPUTarget:               90,
		reportedLevels:          []uint64{},
		reportedCPURequests:     []resource.Quantity{},
		useMetricsAPI:           true,
		expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
			{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededRescale"},
		},
		expectedReportedReconciliationActionLabel:     monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:      monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{},
		expectedReportedMetricComputationErrorLabels:  map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{},
	}
	tc.runTest(t)
}

func TestTooManyReplicas(t *testing.T) {
	tc := testCase{
		minReplicas:             3,
		maxReplicas:             5,
		specReplicas:            10,
		statusReplicas:          10,
		expectedDesiredReplicas: 5,
		CPUTarget:               90,
		reportedLevels:          []uint64{},
		reportedCPURequests:     []resource.Quantity{},
		useMetricsAPI:           true,
		expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
			{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededRescale"},
		},
		expectedReportedReconciliationActionLabel:     monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:      monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{},
		expectedReportedMetricComputationErrorLabels:  map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{},
	}
	tc.runTest(t)
}

func TestMaxReplicas(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             5,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 5,
		CPUTarget:               90,
		reportedLevels:          []uint64{8000, 9500, 1000},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("0.9"), resource.MustParse("1.0"), resource.MustParse("1.1")},
		useMetricsAPI:           true,
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.ScalingLimited,
			Status: v1.ConditionTrue,
			Reason: "TooManyReplicas",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestSuperfluousMetrics(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            4,
		statusReplicas:          4,
		expectedDesiredReplicas: 6,
		CPUTarget:               100,
		reportedLevels:          []uint64{4000, 9500, 3000, 7000, 3200, 2000},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:           true,
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.ScalingLimited,
			Status: v1.ConditionTrue,
			Reason: "TooManyReplicas",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestMissingMetrics(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            4,
		statusReplicas:          4,
		expectedDesiredReplicas: 3,
		CPUTarget:               100,
		reportedLevels:          []uint64{400, 95},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:           true,
		recommendations:         []timestampedRecommendation{},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestEmptyMetrics(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            4,
		statusReplicas:          4,
		expectedDesiredReplicas: 4,
		CPUTarget:               100,
		reportedLevels:          []uint64{},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:           true,
		expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
			{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededGetScale"},
			{Type: autoscalingv2.ScalingActive, Status: v1.ConditionFalse, Reason: "FailedGetResourceMetric"},
		},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelInternal,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelInternal,
		},
	}
	tc.runTest(t)
}

func TestEmptyCPURequest(t *testing.T) {
	tc := testCase{
		minReplicas:             1,
		maxReplicas:             5,
		specReplicas:            1,
		statusReplicas:          1,
		expectedDesiredReplicas: 1,
		CPUTarget:               100,
		reportedLevels:          []uint64{200},
		reportedCPURequests:     []resource.Quantity{},
		useMetricsAPI:           true,
		expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
			{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededGetScale"},
			{Type: autoscalingv2.ScalingActive, Status: v1.ConditionFalse, Reason: "FailedGetResourceMetric"},
		},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelInternal,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelInternal,
		},
	}
	tc.runTest(t)
}

func TestEventCreated(t *testing.T) {
	tc := testCase{
		minReplicas:             1,
		maxReplicas:             5,
		specReplicas:            1,
		statusReplicas:          1,
		expectedDesiredReplicas: 2,
		CPUTarget:               50,
		reportedLevels:          []uint64{200},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("0.2")},
		verifyEvents:            true,
		useMetricsAPI:           true,
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestEventNotCreated(t *testing.T) {
	tc := testCase{
		minReplicas:             1,
		maxReplicas:             5,
		specReplicas:            2,
		statusReplicas:          2,
		expectedDesiredReplicas: 2,
		CPUTarget:               50,
		reportedLevels:          []uint64{200, 200},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("0.4"), resource.MustParse("0.4")},
		verifyEvents:            true,
		useMetricsAPI:           true,
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "ReadyForNewScale",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestMissingReports(t *testing.T) {
	tc := testCase{
		minReplicas:             1,
		maxReplicas:             5,
		specReplicas:            4,
		statusReplicas:          4,
		expectedDesiredReplicas: 2,
		CPUTarget:               50,
		reportedLevels:          []uint64{200},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("0.2")},
		useMetricsAPI:           true,
		recommendations:         []timestampedRecommendation{},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestUpscaleCap(t *testing.T) {
	tc := testCase{
		minReplicas:             1,
		maxReplicas:             100,
		specReplicas:            3,
		statusReplicas:          3,
		scaleUpRules:            generateScalingRules(0, 0, 700, 60, 0),
		initialReplicas:         3,
		expectedDesiredReplicas: 24,
		CPUTarget:               10,
		reportedLevels:          []uint64{100, 200, 300},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("0.1"), resource.MustParse("0.1"), resource.MustParse("0.1")},
		useMetricsAPI:           true,
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.ScalingLimited,
			Status: v1.ConditionTrue,
			Reason: "ScaleUpLimit",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestUpscaleCapGreaterThanMaxReplicas(t *testing.T) {
	// TODO: Remove skip once this issue is resolved: https://github.com/kubernetes/kubernetes/issues/124083
	if goruntime.GOOS == "windows" {
		t.Skip("Skip flaking test on Windows.")
	}
	tc := testCase{
		minReplicas:     1,
		maxReplicas:     20,
		specReplicas:    3,
		statusReplicas:  3,
		scaleUpRules:    generateScalingRules(0, 0, 700, 60, 0),
		initialReplicas: 3,
		// expectedDesiredReplicas would be 24 without maxReplicas
		expectedDesiredReplicas: 20,
		CPUTarget:               10,
		reportedLevels:          []uint64{100, 200, 300},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("0.1"), resource.MustParse("0.1"), resource.MustParse("0.1")},
		useMetricsAPI:           true,
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.ScalingLimited,
			Status: v1.ConditionTrue,
			Reason: "TooManyReplicas",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestMoreReplicasThanSpecNoScale(t *testing.T) {
	// TODO: Remove skip once this issue is resolved: https://github.com/kubernetes/kubernetes/issues/124083
	if goruntime.GOOS == "windows" {
		t.Skip("Skip flaking test on Windows.")
	}
	tc := testCase{
		minReplicas:             1,
		maxReplicas:             8,
		specReplicas:            4,
		statusReplicas:          5, // Deployment update with 25% surge.
		expectedDesiredReplicas: 4,
		CPUTarget:               50,
		reportedLevels:          []uint64{500, 500, 500, 500, 500},
		reportedCPURequests: []resource.Quantity{
			resource.MustParse("1"),
			resource.MustParse("1"),
			resource.MustParse("1"),
			resource.MustParse("1"),
			resource.MustParse("1"),
		},
		useMetricsAPI: true,
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "ReadyForNewScale",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestConditionInvalidSelectorMissing(t *testing.T) {
	tc := testCase{
		minReplicas:             1,
		maxReplicas:             100,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 3,
		CPUTarget:               10,
		reportedLevels:          []uint64{100, 200, 300},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("0.1"), resource.MustParse("0.1"), resource.MustParse("0.1")},
		useMetricsAPI:           true,
		expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
			{
				Type:   autoscalingv2.AbleToScale,
				Status: v1.ConditionTrue,
				Reason: "SucceededGetScale",
			},
			{
				Type:   autoscalingv2.ScalingActive,
				Status: v1.ConditionFalse,
				Reason: "InvalidSelector",
			},
		},
		expectedReportedReconciliationActionLabel:     monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:      monitor.ErrorLabelInternal,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{},
		expectedReportedMetricComputationErrorLabels:  map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{},
	}

	_, _, _, _, testScaleClient := tc.prepareTestClient(t)
	tc.testScaleClient = testScaleClient

	testScaleClient.PrependReactor("get", "replicationcontrollers", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		obj := &autoscalingv1.Scale{
			ObjectMeta: metav1.ObjectMeta{
				Name: tc.resource.name,
			},
			Spec: autoscalingv1.ScaleSpec{
				Replicas: tc.specReplicas,
			},
			Status: autoscalingv1.ScaleStatus{
				Replicas: tc.specReplicas,
			},
		}
		return true, obj, nil
	})

	tc.runTest(t)
}

func TestConditionInvalidSelectorUnparsable(t *testing.T) {
	tc := testCase{
		minReplicas:             1,
		maxReplicas:             100,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 3,
		CPUTarget:               10,
		reportedLevels:          []uint64{100, 200, 300},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("0.1"), resource.MustParse("0.1"), resource.MustParse("0.1")},
		useMetricsAPI:           true,
		expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
			{
				Type:   autoscalingv2.AbleToScale,
				Status: v1.ConditionTrue,
				Reason: "SucceededGetScale",
			},
			{
				Type:   autoscalingv2.ScalingActive,
				Status: v1.ConditionFalse,
				Reason: "InvalidSelector",
			},
		},
		expectedReportedReconciliationActionLabel:     monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:      monitor.ErrorLabelInternal,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{},
		expectedReportedMetricComputationErrorLabels:  map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{},
	}

	_, _, _, _, testScaleClient := tc.prepareTestClient(t)
	tc.testScaleClient = testScaleClient

	testScaleClient.PrependReactor("get", "replicationcontrollers", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		obj := &autoscalingv1.Scale{
			ObjectMeta: metav1.ObjectMeta{
				Name: tc.resource.name,
			},
			Spec: autoscalingv1.ScaleSpec{
				Replicas: tc.specReplicas,
			},
			Status: autoscalingv1.ScaleStatus{
				Replicas: tc.specReplicas,
				Selector: "cheddar cheese",
			},
		}
		return true, obj, nil
	})

	tc.runTest(t)
}

func TestConditionNoAmbiguousSelectorWhenNoSelectorOverlapBetweenHPAs(t *testing.T) {
	hpaSelectors := selectors.NewBiMultimap()
	hpaSelectors.PutSelector(selectors.Key{Name: "test-hpa-2", Namespace: testNamespace}, labels.SelectorFromSet(labels.Set{"cheddar": "cheese"}))

	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 5,
		CPUTarget:               30,
		reportedLevels:          []uint64{300, 500, 700},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:           true,
		hpaSelectors:            hpaSelectors,
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestConditionAmbiguousSelectorWhenFullSelectorOverlapBetweenHPAs(t *testing.T) {
	hpaSelectors := selectors.NewBiMultimap()
	hpaSelectors.PutSelector(selectors.Key{Name: "test-hpa-2", Namespace: testNamespace}, labels.SelectorFromSet(labels.Set{"name": podNamePrefix}))

	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 3,
		CPUTarget:               30,
		reportedLevels:          []uint64{300, 500, 700},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:           true,
		expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
			{
				Type:   autoscalingv2.AbleToScale,
				Status: v1.ConditionTrue,
				Reason: "SucceededGetScale",
			},
			{
				Type:   autoscalingv2.ScalingActive,
				Status: v1.ConditionFalse,
				Reason: "AmbiguousSelector",
			},
		},
		hpaSelectors: hpaSelectors,
		expectedReportedReconciliationActionLabel:     monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:      monitor.ErrorLabelInternal,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{},
		expectedReportedMetricComputationErrorLabels:  map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{},
	}
	tc.runTest(t)
}

func TestConditionAmbiguousSelectorWhenPartialSelectorOverlapBetweenHPAs(t *testing.T) {
	hpaSelectors := selectors.NewBiMultimap()
	hpaSelectors.PutSelector(selectors.Key{Name: "test-hpa-2", Namespace: testNamespace}, labels.SelectorFromSet(labels.Set{"cheddar": "cheese"}))

	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 3,
		CPUTarget:               30,
		reportedLevels:          []uint64{300, 500, 700},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:           true,
		expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
			{
				Type:   autoscalingv2.AbleToScale,
				Status: v1.ConditionTrue,
				Reason: "SucceededGetScale",
			},
			{
				Type:   autoscalingv2.ScalingActive,
				Status: v1.ConditionFalse,
				Reason: "AmbiguousSelector",
			},
		},
		hpaSelectors: hpaSelectors,
		expectedReportedReconciliationActionLabel:     monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:      monitor.ErrorLabelInternal,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{},
		expectedReportedMetricComputationErrorLabels:  map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{},
	}

	testClient, _, _, _, _ := tc.prepareTestClient(t)
	tc.testClient = testClient

	testClient.PrependReactor("list", "pods", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		tc.Lock()
		defer tc.Unlock()

		obj := &v1.PodList{}
		for i := range tc.reportedCPURequests {
			pod := v1.Pod{
				ObjectMeta: metav1.ObjectMeta{
					Name:      fmt.Sprintf("%s-%d", podNamePrefix, i),
					Namespace: testNamespace,
					Labels: map[string]string{
						"name":    podNamePrefix, // selected by the original HPA
						"cheddar": "cheese",      // selected by test-hpa-2
					},
				},
			}
			obj.Items = append(obj.Items, pod)
		}
		return true, obj, nil
	})

	tc.runTest(t)
}

func TestConditionFailedGetMetrics(t *testing.T) {
	targetValue := resource.MustParse("15.0")
	averageValue := resource.MustParse("15.0")
	metricsTargets := map[string][]autoscalingv2.MetricSpec{
		"FailedGetResourceMetric": nil,
		"FailedGetPodsMetric": {
			{
				Type: autoscalingv2.PodsMetricSourceType,
				Pods: &autoscalingv2.PodsMetricSource{
					Metric: autoscalingv2.MetricIdentifier{
						Name: "qps",
					},
					Target: autoscalingv2.MetricTarget{
						Type:         autoscalingv2.AverageValueMetricType,
						AverageValue: &averageValue,
					},
				},
			},
		},
		"FailedGetObjectMetric": {
			{
				Type: autoscalingv2.ObjectMetricSourceType,
				Object: &autoscalingv2.ObjectMetricSource{
					DescribedObject: autoscalingv2.CrossVersionObjectReference{
						APIVersion: "apps/v1",
						Kind:       "Deployment",
						Name:       "some-deployment",
					},
					Metric: autoscalingv2.MetricIdentifier{
						Name: "qps",
					},
					Target: autoscalingv2.MetricTarget{
						Type:  autoscalingv2.ValueMetricType,
						Value: &targetValue,
					},
				},
			},
		},
		"FailedGetExternalMetric": {
			{
				Type: autoscalingv2.ExternalMetricSourceType,
				External: &autoscalingv2.ExternalMetricSource{
					Metric: autoscalingv2.MetricIdentifier{
						Name:     "qps",
						Selector: &metav1.LabelSelector{},
					},
					Target: autoscalingv2.MetricTarget{
						Type:  autoscalingv2.ValueMetricType,
						Value: resource.NewMilliQuantity(300, resource.DecimalSI),
					},
				},
			},
		},
	}

	for reason, specs := range metricsTargets {
		metricType := autoscalingv2.ResourceMetricSourceType
		if specs != nil {
			metricType = specs[0].Type
		}
		tc := testCase{
			minReplicas:             1,
			maxReplicas:             100,
			specReplicas:            3,
			statusReplicas:          3,
			expectedDesiredReplicas: 3,
			CPUTarget:               10,
			reportedLevels:          []uint64{100, 200, 300},
			reportedCPURequests:     []resource.Quantity{resource.MustParse("0.1"), resource.MustParse("0.1"), resource.MustParse("0.1")},
			useMetricsAPI:           true,
			expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
			expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelInternal,
			expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
				metricType: monitor.ActionLabelNone,
			},
			expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
				metricType: monitor.ErrorLabelInternal,
			},
		}
		_, testMetricsClient, testCMClient, testEMClient, _ := tc.prepareTestClient(t)
		tc.testMetricsClient = testMetricsClient
		tc.testCMClient = testCMClient
		tc.testEMClient = testEMClient

		testMetricsClient.PrependReactor("list", "pods", func(action core.Action) (handled bool, ret runtime.Object, err error) {
			return true, &metricsapi.PodMetricsList{}, fmt.Errorf("something went wrong")
		})
		testCMClient.PrependReactor("get", "*", func(action core.Action) (handled bool, ret runtime.Object, err error) {
			return true, &cmapi.MetricValueList{}, fmt.Errorf("something went wrong")
		})
		testEMClient.PrependReactor("list", "*", func(action core.Action) (handled bool, ret runtime.Object, err error) {
			return true, &emapi.ExternalMetricValueList{}, fmt.Errorf("something went wrong")
		})

		tc.expectedConditions = []autoscalingv2.HorizontalPodAutoscalerCondition{
			{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededGetScale"},
			{Type: autoscalingv2.ScalingActive, Status: v1.ConditionFalse, Reason: reason},
		}
		if specs != nil {
			tc.CPUTarget = 0
		} else {
			tc.CPUTarget = 10
		}
		tc.metricsTarget = specs
		tc.runTest(t)
	}
}

func TestConditionInvalidSourceType(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 3,
		CPUTarget:               0,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: "CheddarCheese",
			},
		},
		reportedLevels: []uint64{20000},
		expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
			{
				Type:   autoscalingv2.AbleToScale,
				Status: v1.ConditionTrue,
				Reason: "SucceededGetScale",
			},
			{
				Type:   autoscalingv2.ScalingActive,
				Status: v1.ConditionFalse,
				Reason: "InvalidMetricSourceType",
			},
		},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelInternal,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			// Actually, such an invalid type should be validated in the kube-apiserver and invalid metric type shouldn't be recorded.
			"CheddarCheese": monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			// Actually, such an invalid type should be validated in the kube-apiserver and invalid metric type shouldn't be recorded.
			"CheddarCheese": monitor.ErrorLabelSpec,
		},
	}
	tc.runTest(t)
}

func TestConditionFailedGetScale(t *testing.T) {
	tc := testCase{
		minReplicas:             1,
		maxReplicas:             100,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 3,
		CPUTarget:               10,
		reportedLevels:          []uint64{100, 200, 300},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("0.1"), resource.MustParse("0.1"), resource.MustParse("0.1")},
		useMetricsAPI:           true,
		expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
			{
				Type:   autoscalingv2.AbleToScale,
				Status: v1.ConditionFalse,
				Reason: "FailedGetScale",
			},
		},
		expectedReportedReconciliationActionLabel:     monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:      monitor.ErrorLabelInternal,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{},
		expectedReportedMetricComputationErrorLabels:  map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{},
	}

	_, _, _, _, testScaleClient := tc.prepareTestClient(t)
	tc.testScaleClient = testScaleClient

	testScaleClient.PrependReactor("get", "replicationcontrollers", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		return true, &autoscalingv1.Scale{}, fmt.Errorf("something went wrong")
	})

	tc.runTest(t)
}

func TestConditionFailedUpdateScale(t *testing.T) {
	tc := testCase{
		minReplicas:             1,
		maxReplicas:             5,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 3,
		CPUTarget:               100,
		reportedLevels:          []uint64{150, 150, 150},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("0.1"), resource.MustParse("0.1"), resource.MustParse("0.1")},
		useMetricsAPI:           true,
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionFalse,
			Reason: "FailedUpdateScale",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelInternal,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}

	_, _, _, _, testScaleClient := tc.prepareTestClient(t)
	tc.testScaleClient = testScaleClient

	testScaleClient.PrependReactor("update", "replicationcontrollers", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		return true, &autoscalingv1.Scale{}, fmt.Errorf("something went wrong")
	})

	tc.runTest(t)
}

func TestNoBackoffUpscaleCM(t *testing.T) {
	averageValue := resource.MustParse("15.0")
	time := metav1.Time{Time: time.Now()}
	tc := testCase{
		minReplicas:             1,
		maxReplicas:             5,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 4,
		CPUTarget:               0,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.PodsMetricSourceType,
				Pods: &autoscalingv2.PodsMetricSource{
					Metric: autoscalingv2.MetricIdentifier{
						Name: "qps",
					},
					Target: autoscalingv2.MetricTarget{
						Type:         autoscalingv2.AverageValueMetricType,
						AverageValue: &averageValue,
					},
				},
			},
		},
		reportedLevels:      []uint64{20000, 10000, 30000},
		reportedCPURequests: []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		//useMetricsAPI:       true,
		lastScaleTime: &time,
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "ReadyForNewScale",
		}, autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "SucceededRescale",
		}, autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.ScalingLimited,
			Status: v1.ConditionFalse,
			Reason: "DesiredWithinRange",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.PodsMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.PodsMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestNoBackoffUpscaleCMNoBackoffCpu(t *testing.T) {
	averageValue := resource.MustParse("15.0")
	time := metav1.Time{Time: time.Now()}
	tc := testCase{
		minReplicas:             1,
		maxReplicas:             5,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 5,
		CPUTarget:               10,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.PodsMetricSourceType,
				Pods: &autoscalingv2.PodsMetricSource{
					Metric: autoscalingv2.MetricIdentifier{
						Name: "qps",
					},
					Target: autoscalingv2.MetricTarget{
						Type:         autoscalingv2.AverageValueMetricType,
						AverageValue: &averageValue,
					},
				},
			},
		},
		reportedLevels:      []uint64{20000, 10000, 30000},
		reportedCPURequests: []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:       true,
		lastScaleTime:       &time,
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "ReadyForNewScale",
		}, autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "SucceededRescale",
		}, autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.ScalingLimited,
			Status: v1.ConditionTrue,
			Reason: "TooManyReplicas",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
			autoscalingv2.PodsMetricSourceType:     monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
			autoscalingv2.PodsMetricSourceType:     monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

func TestStabilizeDownscale(t *testing.T) {
	tc := testCase{
		minReplicas:             1,
		maxReplicas:             5,
		specReplicas:            4,
		statusReplicas:          4,
		expectedDesiredReplicas: 4,
		CPUTarget:               100,
		reportedLevels:          []uint64{50, 50, 50},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("0.1"), resource.MustParse("0.1"), resource.MustParse("0.1")},
		useMetricsAPI:           true,
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "ReadyForNewScale",
		}, autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "ScaleDownStabilized",
		}),
		recommendations: []timestampedRecommendation{
			{10, time.Now().Add(-10 * time.Minute)},
			{4, time.Now().Add(-1 * time.Minute)},
		},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc.runTest(t)
}

// TestComputedToleranceAlgImplementation is a regression test which
// back-calculates a minimal percentage for downscaling based on a small percentage
// increase in pod utilization which is calibrated against the tolerance value.
func TestComputedToleranceAlgImplementation(t *testing.T) {

	startPods := int32(10)
	// 150 mCPU per pod.
	totalUsedCPUOfAllPods := uint64(startPods * 150)
	// Each pod starts out asking for 2X what is really needed.
	// This means we will have a 50% ratio of used/requested
	totalRequestedCPUOfAllPods := int32(2 * totalUsedCPUOfAllPods)
	requestedToUsed := float64(totalRequestedCPUOfAllPods / int32(totalUsedCPUOfAllPods))
	// Spread the amount we ask over 10 pods.  We can add some jitter later in reportedLevels.
	perPodRequested := totalRequestedCPUOfAllPods / startPods

	// Force a minimal scaling event by satisfying  (tolerance < 1 - resourcesUsedRatio).
	target := math.Abs(1/(requestedToUsed*(1-defaultTestingTolerance))) + .01
	finalCPUPercentTarget := int32(target * 100)
	resourcesUsedRatio := float64(totalUsedCPUOfAllPods) / float64(float64(totalRequestedCPUOfAllPods)*target)

	// i.e. .60 * 20 -> scaled down expectation.
	finalPods := int32(math.Ceil(resourcesUsedRatio * float64(startPods)))

	// To breach tolerance we will create a utilization ratio difference of tolerance to usageRatioToleranceValue)
	tc1 := testCase{
		minReplicas:             0,
		maxReplicas:             1000,
		specReplicas:            startPods,
		statusReplicas:          startPods,
		expectedDesiredReplicas: finalPods,
		CPUTarget:               finalCPUPercentTarget,
		reportedLevels: []uint64{
			totalUsedCPUOfAllPods / 10,
			totalUsedCPUOfAllPods / 10,
			totalUsedCPUOfAllPods / 10,
			totalUsedCPUOfAllPods / 10,
			totalUsedCPUOfAllPods / 10,
			totalUsedCPUOfAllPods / 10,
			totalUsedCPUOfAllPods / 10,
			totalUsedCPUOfAllPods / 10,
			totalUsedCPUOfAllPods / 10,
			totalUsedCPUOfAllPods / 10,
		},
		reportedCPURequests: []resource.Quantity{
			resource.MustParse(fmt.Sprint(perPodRequested+100) + "m"),
			resource.MustParse(fmt.Sprint(perPodRequested-100) + "m"),
			resource.MustParse(fmt.Sprint(perPodRequested+10) + "m"),
			resource.MustParse(fmt.Sprint(perPodRequested-10) + "m"),
			resource.MustParse(fmt.Sprint(perPodRequested+2) + "m"),
			resource.MustParse(fmt.Sprint(perPodRequested-2) + "m"),
			resource.MustParse(fmt.Sprint(perPodRequested+1) + "m"),
			resource.MustParse(fmt.Sprint(perPodRequested-1) + "m"),
			resource.MustParse(fmt.Sprint(perPodRequested) + "m"),
			resource.MustParse(fmt.Sprint(perPodRequested) + "m"),
		},
		useMetricsAPI:   true,
		recommendations: []timestampedRecommendation{},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc1.runTest(t)

	target = math.Abs(1/(requestedToUsed*(1-defaultTestingTolerance))) + .004
	finalCPUPercentTarget = int32(target * 100)
	tc2 := testCase{
		minReplicas:             0,
		maxReplicas:             1000,
		specReplicas:            startPods,
		statusReplicas:          startPods,
		expectedDesiredReplicas: startPods,
		CPUTarget:               finalCPUPercentTarget,
		reportedLevels: []uint64{
			totalUsedCPUOfAllPods / 10,
			totalUsedCPUOfAllPods / 10,
			totalUsedCPUOfAllPods / 10,
			totalUsedCPUOfAllPods / 10,
			totalUsedCPUOfAllPods / 10,
			totalUsedCPUOfAllPods / 10,
			totalUsedCPUOfAllPods / 10,
			totalUsedCPUOfAllPods / 10,
			totalUsedCPUOfAllPods / 10,
			totalUsedCPUOfAllPods / 10,
		},
		reportedCPURequests: []resource.Quantity{
			resource.MustParse(fmt.Sprint(perPodRequested+100) + "m"),
			resource.MustParse(fmt.Sprint(perPodRequested-100) + "m"),
			resource.MustParse(fmt.Sprint(perPodRequested+10) + "m"),
			resource.MustParse(fmt.Sprint(perPodRequested-10) + "m"),
			resource.MustParse(fmt.Sprint(perPodRequested+2) + "m"),
			resource.MustParse(fmt.Sprint(perPodRequested-2) + "m"),
			resource.MustParse(fmt.Sprint(perPodRequested+1) + "m"),
			resource.MustParse(fmt.Sprint(perPodRequested-1) + "m"),
			resource.MustParse(fmt.Sprint(perPodRequested) + "m"),
			resource.MustParse(fmt.Sprint(perPodRequested) + "m"),
		},
		useMetricsAPI:   true,
		recommendations: []timestampedRecommendation{},
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "ReadyForNewScale",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	tc2.runTest(t)
}

func TestScaleUpRCImmediately(t *testing.T) {
	time := metav1.Time{Time: time.Now()}
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            1,
		statusReplicas:          1,
		expectedDesiredReplicas: 2,
		verifyCPUCurrent:        false,
		reportedLevels:          []uint64{0, 0, 0, 0},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:           true,
		lastScaleTime:           &time,
		expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
			{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededRescale"},
		},
		expectedReportedReconciliationActionLabel:     monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:      monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{},
		expectedReportedMetricComputationErrorLabels:  map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{},
	}
	tc.runTest(t)
}

func TestScaleDownRCImmediately(t *testing.T) {
	time := metav1.Time{Time: time.Now()}
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             5,
		specReplicas:            6,
		statusReplicas:          6,
		expectedDesiredReplicas: 5,
		CPUTarget:               50,
		reportedLevels:          []uint64{8000, 9500, 1000},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("0.9"), resource.MustParse("1.0"), resource.MustParse("1.1")},
		useMetricsAPI:           true,
		lastScaleTime:           &time,
		expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
			{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededRescale"},
		},
		expectedReportedReconciliationActionLabel:     monitor.ActionLabelScaleDown,
		expectedReportedReconciliationErrorLabel:      monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{},
		expectedReportedMetricComputationErrorLabels:  map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{},
	}
	tc.runTest(t)
}

func TestAvoidUnnecessaryUpdates(t *testing.T) {
	now := metav1.Time{Time: time.Now().Add(-time.Hour)}
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            2,
		statusReplicas:          2,
		expectedDesiredReplicas: 2,
		CPUTarget:               30,
		CPUCurrent:              40,
		verifyCPUCurrent:        true,
		reportedLevels:          []uint64{400, 500, 700},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		reportedPodStartTime:    []metav1.Time{coolCPUCreationTime(), hotCPUCreationTime(), hotCPUCreationTime()},
		useMetricsAPI:           true,
		lastScaleTime:           &now,
		recommendations:         []timestampedRecommendation{},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleDown,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}
	testClient, _, _, _, _ := tc.prepareTestClient(t)
	tc.testClient = testClient
	testClient.PrependReactor("list", "horizontalpodautoscalers", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		tc.Lock()
		defer tc.Unlock()
		// fake out the verification logic and mark that we're done processing
		go func() {
			// wait a tick and then mark that we're finished (otherwise, we have no
			// way to indicate that we're finished, because the function decides not to do anything)
			time.Sleep(1 * time.Second)
			tc.Lock()
			tc.statusUpdated = true
			tc.Unlock()
			tc.processed <- "test-hpa"
		}()

		var eighty int32 = 80

		quantity := resource.MustParse("400m")
		obj := &autoscalingv2.HorizontalPodAutoscalerList{
			Items: []autoscalingv2.HorizontalPodAutoscaler{
				{
					ObjectMeta: metav1.ObjectMeta{
						Name:      "test-hpa",
						Namespace: "test-namespace",
					},
					Spec: autoscalingv2.HorizontalPodAutoscalerSpec{
						ScaleTargetRef: autoscalingv2.CrossVersionObjectReference{
							Kind:       "ReplicationController",
							Name:       "test-rc",
							APIVersion: "v1",
						},
						Metrics: []autoscalingv2.MetricSpec{{
							Type: autoscalingv2.ResourceMetricSourceType,
							Resource: &autoscalingv2.ResourceMetricSource{
								Name: v1.ResourceCPU,
								Target: autoscalingv2.MetricTarget{
									Type: autoscalingv2.UtilizationMetricType,
									// TODO: Change this to &tc.CPUTarget and the expected ScaleLimited
									//       condition to False. This test incorrectly leaves the v1
									//       HPA field TargetCPUUtilizization field blank and the
									//       controller defaults to a target of 80. So the test relies
									//       on downscale stabilization to prevent a scale change.
									AverageUtilization: &eighty,
								},
							},
						}},
						MinReplicas: &tc.minReplicas,
						MaxReplicas: tc.maxReplicas,
					},
					Status: autoscalingv2.HorizontalPodAutoscalerStatus{
						CurrentReplicas: tc.specReplicas,
						DesiredReplicas: tc.specReplicas,
						LastScaleTime:   tc.lastScaleTime,
						CurrentMetrics: []autoscalingv2.MetricStatus{
							{
								Type: autoscalingv2.ResourceMetricSourceType,
								Resource: &autoscalingv2.ResourceMetricStatus{
									Name: v1.ResourceCPU,
									Current: autoscalingv2.MetricValueStatus{
										AverageValue:       &quantity,
										AverageUtilization: &tc.CPUCurrent,
									},
								},
							},
						},
						Conditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
							{
								Type:               autoscalingv2.AbleToScale,
								Status:             v1.ConditionTrue,
								LastTransitionTime: *tc.lastScaleTime,
								Reason:             "ReadyForNewScale",
								Message:            "recommended size matches current size",
							},
							{
								Type:               autoscalingv2.ScalingActive,
								Status:             v1.ConditionTrue,
								LastTransitionTime: *tc.lastScaleTime,
								Reason:             "ValidMetricFound",
								Message:            "the HPA was able to successfully calculate a replica count from cpu resource utilization (percentage of request)",
							},
							{
								Type:               autoscalingv2.ScalingLimited,
								Status:             v1.ConditionTrue,
								LastTransitionTime: *tc.lastScaleTime,
								Reason:             "TooFewReplicas",
								Message:            "the desired replica count is less than the minimum replica count",
							},
						},
					},
				},
			},
		}

		return true, obj, nil
	})
	testClient.PrependReactor("update", "horizontalpodautoscalers", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		assert.Fail(t, "should not have attempted to update the HPA when nothing changed")
		// mark that we've processed this HPA
		tc.processed <- ""
		return true, nil, fmt.Errorf("unexpected call")
	})

	controller, informerFactory := tc.setupController(t)
	tc.runTestWithController(t, controller, informerFactory)
}

func TestConvertDesiredReplicasWithRules(t *testing.T) {
	conversionTestCases := []struct {
		currentReplicas                  int32
		expectedDesiredReplicas          int32
		hpaMinReplicas                   int32
		hpaMaxReplicas                   int32
		expectedConvertedDesiredReplicas int32
		expectedCondition                string
		annotation                       string
	}{
		{
			currentReplicas:                  5,
			expectedDesiredReplicas:          7,
			hpaMinReplicas:                   3,
			hpaMaxReplicas:                   8,
			expectedConvertedDesiredReplicas: 7,
			expectedCondition:                "DesiredWithinRange",
			annotation:                       "prenormalized desired replicas within range",
		},
		{
			currentReplicas:                  3,
			expectedDesiredReplicas:          1,
			hpaMinReplicas:                   2,
			hpaMaxReplicas:                   8,
			expectedConvertedDesiredReplicas: 2,
			expectedCondition:                "TooFewReplicas",
			annotation:                       "prenormalized desired replicas < minReplicas",
		},
		{
			currentReplicas:                  1,
			expectedDesiredReplicas:          0,
			hpaMinReplicas:                   0,
			hpaMaxReplicas:                   10,
			expectedConvertedDesiredReplicas: 0,
			expectedCondition:                "DesiredWithinRange",
			annotation:                       "prenormalized desired zeroed replicas within range",
		},
		{
			currentReplicas:                  20,
			expectedDesiredReplicas:          1000,
			hpaMinReplicas:                   1,
			hpaMaxReplicas:                   10,
			expectedConvertedDesiredReplicas: 10,
			expectedCondition:                "TooManyReplicas",
			annotation:                       "maxReplicas is the limit because maxReplicas < scaleUpLimit",
		},
		{
			currentReplicas:                  3,
			expectedDesiredReplicas:          1000,
			hpaMinReplicas:                   1,
			hpaMaxReplicas:                   2000,
			expectedConvertedDesiredReplicas: calculateScaleUpLimit(3),
			expectedCondition:                "ScaleUpLimit",
			annotation:                       "scaleUpLimit is the limit because scaleUpLimit < maxReplicas",
		},
	}

	for _, ctc := range conversionTestCases {
		t.Run(ctc.annotation, func(t *testing.T) {
			actualConvertedDesiredReplicas, actualCondition, _ := convertDesiredReplicasWithRules(
				ctc.currentReplicas, ctc.expectedDesiredReplicas, ctc.hpaMinReplicas, ctc.hpaMaxReplicas,
			)

			assert.Equal(t, ctc.expectedConvertedDesiredReplicas, actualConvertedDesiredReplicas, ctc.annotation)
			assert.Equal(t, ctc.expectedCondition, actualCondition, ctc.annotation)
		})
	}
}

func TestCalculateScaleUpLimitWithScalingRules(t *testing.T) {
	policy := autoscalingv2.MinChangePolicySelect

	calculated := calculateScaleUpLimitWithScalingRules(1, []timestampedScaleEvent{}, []timestampedScaleEvent{}, &autoscalingv2.HPAScalingRules{
		StabilizationWindowSeconds: ptr.To(int32(300)),
		SelectPolicy:               &policy,
		Policies: []autoscalingv2.HPAScalingPolicy{
			{
				Type:          autoscalingv2.PodsScalingPolicy,
				Value:         2,
				PeriodSeconds: 60,
			},
			{
				Type:          autoscalingv2.PercentScalingPolicy,
				Value:         50,
				PeriodSeconds: 60,
			},
		},
	})
	assert.Equal(t, int32(2), calculated)
}

func TestCalculateScaleDownLimitWithBehaviors(t *testing.T) {
	policy := autoscalingv2.MinChangePolicySelect

	calculated := calculateScaleDownLimitWithBehaviors(5, []timestampedScaleEvent{}, []timestampedScaleEvent{}, &autoscalingv2.HPAScalingRules{
		StabilizationWindowSeconds: ptr.To(int32(300)),
		SelectPolicy:               &policy,
		Policies: []autoscalingv2.HPAScalingPolicy{
			{
				Type:          autoscalingv2.PodsScalingPolicy,
				Value:         2,
				PeriodSeconds: 60,
			},
			{
				Type:          autoscalingv2.PercentScalingPolicy,
				Value:         50,
				PeriodSeconds: 60,
			},
		},
	})
	assert.Equal(t, int32(3), calculated)
}

func generateScalingRules(pods, podsPeriod, percent, percentPeriod, stabilizationWindow int32) *autoscalingv2.HPAScalingRules {
	policy := autoscalingv2.MaxChangePolicySelect
	directionBehavior := autoscalingv2.HPAScalingRules{
		StabilizationWindowSeconds: ptr.To(stabilizationWindow),
		SelectPolicy:               &policy,
	}
	if pods != 0 {
		directionBehavior.Policies = append(directionBehavior.Policies,
			autoscalingv2.HPAScalingPolicy{Type: autoscalingv2.PodsScalingPolicy, Value: pods, PeriodSeconds: podsPeriod})
	}
	if percent != 0 {
		directionBehavior.Policies = append(directionBehavior.Policies,
			autoscalingv2.HPAScalingPolicy{Type: autoscalingv2.PercentScalingPolicy, Value: percent, PeriodSeconds: percentPeriod})
	}
	return &directionBehavior
}

// generateEventsUniformDistribution generates events that uniformly spread in the time window
//
//	time.Now()-periodSeconds  ; time.Now()
//
// It split the time window into several segments (by the number of events) and put the event in the center of the segment
// it is needed if you want to create events for several policies (to check how "outdated" flag is set).
// E.g. generateEventsUniformDistribution([]int{1,2,3,4}, 120) will spread events uniformly for the last 120 seconds:
//
//	1          2          3          4
//
// -----------------------------------------------
//
//	^          ^          ^          ^          ^
//
// -120s      -90s       -60s       -30s       now()
// And we can safely have two different stabilizationWindows:
//   - 60s (guaranteed to have last half of events)
//   - 120s (guaranteed to have all events)
func generateEventsUniformDistribution(rawEvents []int, periodSeconds int) []timestampedScaleEvent {
	events := make([]timestampedScaleEvent, len(rawEvents))
	segmentDuration := float64(periodSeconds) / float64(len(rawEvents))
	for idx, event := range rawEvents {
		segmentBoundary := time.Duration(float64(periodSeconds) - segmentDuration*float64(idx+1) + segmentDuration/float64(2))
		events[idx] = timestampedScaleEvent{
			replicaChange: int32(event),
			timestamp:     time.Now().Add(-time.Second * segmentBoundary),
		}
	}
	return events
}

func TestNormalizeDesiredReplicas(t *testing.T) {
	tests := []struct {
		name                         string
		key                          string
		recommendations              []timestampedRecommendation
		prenormalizedDesiredReplicas int32
		expectedStabilizedReplicas   int32
		expectedLogLength            int
	}{
		{
			"empty log",
			"",
			[]timestampedRecommendation{},
			5,
			5,
			1,
		},
		{
			"stabilize",
			"",
			[]timestampedRecommendation{
				{4, time.Now().Add(-2 * time.Minute)},
				{5, time.Now().Add(-1 * time.Minute)},
			},
			3,
			5,
			3,
		},
		{
			"no stabilize",
			"",
			[]timestampedRecommendation{
				{1, time.Now().Add(-2 * time.Minute)},
				{2, time.Now().Add(-1 * time.Minute)},
			},
			3,
			3,
			3,
		},
		{
			"no stabilize - old recommendations",
			"",
			[]timestampedRecommendation{
				{10, time.Now().Add(-10 * time.Minute)},
				{9, time.Now().Add(-9 * time.Minute)},
			},
			3,
			3,
			2,
		},
		{
			"stabilize - old recommendations",
			"",
			[]timestampedRecommendation{
				{10, time.Now().Add(-10 * time.Minute)},
				{4, time.Now().Add(-1 * time.Minute)},
				{5, time.Now().Add(-2 * time.Minute)},
				{9, time.Now().Add(-9 * time.Minute)},
			},
			3,
			5,
			4,
		},
	}
	for _, tc := range tests {
		hc := HorizontalController{
			downscaleStabilisationWindow: 5 * time.Minute,
			recommendations: map[string][]timestampedRecommendation{
				tc.key: tc.recommendations,
			},
		}
		r := hc.stabilizeRecommendation(tc.key, tc.prenormalizedDesiredReplicas)
		if r != tc.expectedStabilizedReplicas {
			t.Errorf("[%s] got %d stabilized replicas, expected %d", tc.name, r, tc.expectedStabilizedReplicas)
		}
		if len(hc.recommendations[tc.key]) != tc.expectedLogLength {
			t.Errorf("[%s] after  stabilization recommendations log has %d entries, expected %d", tc.name, len(hc.recommendations[tc.key]), tc.expectedLogLength)
		}
	}
}

func TestScalingWithRules(t *testing.T) {
	type TestCase struct {
		name string
		key  string
		// controller arguments
		scaleUpEvents   []timestampedScaleEvent
		scaleDownEvents []timestampedScaleEvent
		// HPA Spec arguments
		specMinReplicas int32
		specMaxReplicas int32
		scaleUpRules    *autoscalingv2.HPAScalingRules
		scaleDownRules  *autoscalingv2.HPAScalingRules
		// external world state
		currentReplicas              int32
		prenormalizedDesiredReplicas int32
		// test expected result
		expectedReplicas  int32
		expectedCondition string

		testThis bool
	}

	tests := []TestCase{
		{
			currentReplicas:              5,
			prenormalizedDesiredReplicas: 7,
			specMinReplicas:              3,
			specMaxReplicas:              8,
			expectedReplicas:             7,
			expectedCondition:            "DesiredWithinRange",
			name:                         "prenormalized desired replicas within range",
		},
		{
			currentReplicas:              3,
			prenormalizedDesiredReplicas: 1,
			specMinReplicas:              2,
			specMaxReplicas:              8,
			expectedReplicas:             2,
			expectedCondition:            "TooFewReplicas",
			name:                         "prenormalized desired replicas < minReplicas",
		},
		{
			currentReplicas:              1,
			prenormalizedDesiredReplicas: 0,
			specMinReplicas:              0,
			specMaxReplicas:              10,
			expectedReplicas:             0,
			expectedCondition:            "DesiredWithinRange",
			name:                         "prenormalized desired replicas within range when minReplicas is 0",
		},
		{
			currentReplicas:              20,
			prenormalizedDesiredReplicas: 1000,
			specMinReplicas:              1,
			specMaxReplicas:              10,
			expectedReplicas:             10,
			expectedCondition:            "TooManyReplicas",
			name:                         "maxReplicas is the limit because maxReplicas < scaleUpLimit",
		},
		{
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 1000,
			specMinReplicas:              100,
			specMaxReplicas:              150,
			expectedReplicas:             150,
			expectedCondition:            "TooManyReplicas",
			name:                         "desired replica count is more than the maximum replica count",
		},
		{
			currentReplicas:              3,
			prenormalizedDesiredReplicas: 1000,
			specMinReplicas:              1,
			specMaxReplicas:              2000,
			expectedReplicas:             4,
			expectedCondition:            "ScaleUpLimit",
			scaleUpRules:                 generateScalingRules(0, 0, 1, 60, 0),
			name:                         "scaleUpLimit is the limit because scaleUpLimit < maxReplicas with user policies",
		},
		{
			currentReplicas:              1000,
			prenormalizedDesiredReplicas: 3,
			specMinReplicas:              3,
			specMaxReplicas:              2000,
			scaleDownRules:               generateScalingRules(20, 60, 0, 0, 0),
			expectedReplicas:             980,
			expectedCondition:            "ScaleDownLimit",
			name:                         "scaleDownLimit is the limit because scaleDownLimit > minReplicas with user defined policies",
			testThis:                     true,
		},
		// ScaleUp without PeriodSeconds usage
		{
			name:                         "scaleUp with default behavior",
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			currentReplicas:              10,
			prenormalizedDesiredReplicas: 50,
			expectedReplicas:             20,
			expectedCondition:            "ScaleUpLimit",
		},
		{
			name:                         "scaleUp with pods policy larger than percent policy",
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleUpRules:                 generateScalingRules(100, 60, 100, 60, 0),
			currentReplicas:              10,
			prenormalizedDesiredReplicas: 500,
			expectedReplicas:             110,
			expectedCondition:            "ScaleUpLimit",
		},
		{
			name:                         "scaleUp with percent policy larger than pods policy",
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleUpRules:                 generateScalingRules(2, 60, 100, 60, 0),
			currentReplicas:              10,
			prenormalizedDesiredReplicas: 500,
			expectedReplicas:             20,
			expectedCondition:            "ScaleUpLimit",
		},
		{
			name:                         "scaleUp with spec MaxReplicas limitation with large pod policy",
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleUpRules:                 generateScalingRules(100, 60, 0, 0, 0),
			currentReplicas:              10,
			prenormalizedDesiredReplicas: 50,
			expectedReplicas:             50,
			expectedCondition:            "DesiredWithinRange",
		},
		{
			name:                         "scaleUp with spec MaxReplicas limitation with large percent policy",
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleUpRules:                 generateScalingRules(10000, 60, 0, 0, 0),
			currentReplicas:              10,
			prenormalizedDesiredReplicas: 50,
			expectedReplicas:             50,
			expectedCondition:            "DesiredWithinRange",
		},
		{
			name:                         "scaleUp with pod policy limitation",
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleUpRules:                 generateScalingRules(30, 60, 0, 0, 0),
			currentReplicas:              10,
			prenormalizedDesiredReplicas: 50,
			expectedReplicas:             40,
			expectedCondition:            "ScaleUpLimit",
		},
		{
			name:                         "scaleUp with percent policy limitation",
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleUpRules:                 generateScalingRules(0, 0, 200, 60, 0),
			currentReplicas:              10,
			prenormalizedDesiredReplicas: 50,
			expectedReplicas:             30,
			expectedCondition:            "ScaleUpLimit",
		},
		{
			name:                         "scaleDown with percent policy larger than pod policy",
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleDownRules:               generateScalingRules(20, 60, 1, 60, 300),
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 2,
			expectedReplicas:             80,
			expectedCondition:            "ScaleDownLimit",
		},
		{
			name:                         "scaleDown with pod policy larger than percent policy",
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleDownRules:               generateScalingRules(2, 60, 1, 60, 300),
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 2,
			expectedReplicas:             98,
			expectedCondition:            "ScaleDownLimit",
		},
		{
			name:                         "scaleDown with spec MinReplicas=nil limitation with large pod policy",
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleDownRules:               generateScalingRules(100, 60, 0, 0, 300),
			currentReplicas:              10,
			prenormalizedDesiredReplicas: 0,
			expectedReplicas:             1,
			expectedCondition:            "TooFewReplicas",
		},
		{
			name:                         "scaleDown with spec MinReplicas limitation with large pod policy",
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleDownRules:               generateScalingRules(100, 60, 0, 0, 300),
			currentReplicas:              10,
			prenormalizedDesiredReplicas: 0,
			expectedReplicas:             1,
			expectedCondition:            "TooFewReplicas",
		},
		{
			name:                         "scaleDown with spec MinReplicas limitation with large percent policy",
			specMinReplicas:              5,
			specMaxReplicas:              1000,
			scaleDownRules:               generateScalingRules(0, 0, 100, 60, 300),
			currentReplicas:              10,
			prenormalizedDesiredReplicas: 2,
			expectedReplicas:             5,
			expectedCondition:            "TooFewReplicas",
		},
		{
			name:                         "scaleDown with pod policy limitation",
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleDownRules:               generateScalingRules(5, 60, 0, 0, 300),
			currentReplicas:              10,
			prenormalizedDesiredReplicas: 2,
			expectedReplicas:             5,
			expectedCondition:            "ScaleDownLimit",
		},
		{
			name:                         "scaleDown with percent policy limitation",
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleDownRules:               generateScalingRules(0, 0, 50, 60, 300),
			currentReplicas:              10,
			prenormalizedDesiredReplicas: 5,
			expectedReplicas:             5,
			expectedCondition:            "DesiredWithinRange",
		},
		{
			name:                         "scaleUp with spec MaxReplicas limitation with large pod policy and events",
			scaleUpEvents:                generateEventsUniformDistribution([]int{1, 5, 9}, 120),
			specMinReplicas:              1,
			specMaxReplicas:              200,
			scaleUpRules:                 generateScalingRules(300, 60, 0, 0, 0),
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 500,
			expectedReplicas:             200, // 200 < 100 - 15 + 300
			expectedCondition:            "TooManyReplicas",
		},
		{
			name:                         "scaleUp with spec MaxReplicas limitation with large percent policy and events",
			scaleUpEvents:                generateEventsUniformDistribution([]int{1, 5, 9}, 120),
			specMinReplicas:              1,
			specMaxReplicas:              200,
			scaleUpRules:                 generateScalingRules(0, 0, 10000, 60, 0),
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 500,
			expectedReplicas:             200,
			expectedCondition:            "TooManyReplicas",
		},
		{
			// corner case for calculating the scaleUpLimit, when we changed pod policy after a lot of scaleUp events
			// in this case we shouldn't allow scale up, though, the naive formula will suggest that scaleUplimit is less then CurrentReplicas (100-15+5 < 100)
			name:                         "scaleUp with currentReplicas limitation with rate.PeriodSeconds with a lot of recent scale up events",
			scaleUpEvents:                generateEventsUniformDistribution([]int{1, 5, 9}, 120),
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleUpRules:                 generateScalingRules(5, 120, 0, 0, 0),
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 500,
			expectedReplicas:             100, // 120 seconds ago we had (100 - 15) replicas, now the rate.Pods = 5,
			expectedCondition:            "ScaleUpLimit",
		},
		{
			name:                         "scaleUp with pod policy and previous scale up events",
			scaleUpEvents:                generateEventsUniformDistribution([]int{1, 5, 9}, 120),
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleUpRules:                 generateScalingRules(150, 120, 0, 0, 0),
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 500,
			expectedReplicas:             235, // 100 - 15 + 150
			expectedCondition:            "ScaleUpLimit",
		},
		{
			name:                         "scaleUp with percent policy and previous scale up events",
			scaleUpEvents:                generateEventsUniformDistribution([]int{1, 5, 9}, 120),
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleUpRules:                 generateScalingRules(0, 0, 200, 120, 0),
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 500,
			expectedReplicas:             255, // (100 - 15) + 200%
			expectedCondition:            "ScaleUpLimit",
		},
		{
			name:                         "scaleUp with percent policy and previous scale up and down events",
			scaleUpEvents:                generateEventsUniformDistribution([]int{4}, 120),
			scaleDownEvents:              generateEventsUniformDistribution([]int{2}, 120),
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleUpRules:                 generateScalingRules(0, 0, 300, 300, 0),
			currentReplicas:              6,
			prenormalizedDesiredReplicas: 24,
			expectedReplicas:             16,
			expectedCondition:            "ScaleUpLimit",
		},
		// ScaleDown with PeriodSeconds usage
		{
			name:                         "scaleDown with default policy and previous events",
			scaleDownEvents:              generateEventsUniformDistribution([]int{1, 5, 9}, 120),
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			currentReplicas:              10,
			prenormalizedDesiredReplicas: 5,
			expectedReplicas:             5, // without scaleDown rate limitations the PeriodSeconds does not influence anything
			expectedCondition:            "DesiredWithinRange",
		},
		{
			name:                         "scaleDown with spec MinReplicas=nil limitation with large pod policy and previous events",
			scaleDownEvents:              generateEventsUniformDistribution([]int{1, 5, 9}, 120),
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleDownRules:               generateScalingRules(115, 120, 0, 0, 300),
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 0,
			expectedReplicas:             1,
			expectedCondition:            "TooFewReplicas",
		},
		{
			name:                         "scaleDown with spec MinReplicas limitation with large pod policy and previous events",
			scaleDownEvents:              generateEventsUniformDistribution([]int{1, 5, 9}, 120),
			specMinReplicas:              5,
			specMaxReplicas:              1000,
			scaleDownRules:               generateScalingRules(130, 120, 0, 0, 300),
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 0,
			expectedReplicas:             5,
			expectedCondition:            "TooFewReplicas",
		},
		{
			name:                         "scaleDown with spec MinReplicas limitation with large percent policy and previous events",
			scaleDownEvents:              generateEventsUniformDistribution([]int{1, 5, 9}, 120),
			specMinReplicas:              5,
			specMaxReplicas:              1000,
			scaleDownRules:               generateScalingRules(0, 0, 100, 120, 300), // 100% removal - is always to 0 => limited by MinReplicas
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 2,
			expectedReplicas:             5,
			expectedCondition:            "TooFewReplicas",
		},
		{
			name:                         "scaleDown with pod policy limitation and previous events",
			scaleDownEvents:              generateEventsUniformDistribution([]int{1, 5, 9}, 120),
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleDownRules:               generateScalingRules(5, 120, 0, 0, 300),
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 2,
			expectedReplicas:             100, // 100 + 15 - 5
			expectedCondition:            "ScaleDownLimit",
		},
		{
			name:                         "scaleDown with percent policy limitation and previous events",
			scaleDownEvents:              generateEventsUniformDistribution([]int{2, 4, 6}, 120),
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleDownRules:               generateScalingRules(0, 0, 50, 120, 300),
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 0,
			expectedReplicas:             56, // (100 + 12) - 50%
			expectedCondition:            "ScaleDownLimit",
		},
		{
			name:                         "scaleDown with percent policy and previous scale up and down events",
			scaleUpEvents:                generateEventsUniformDistribution([]int{2}, 120),
			scaleDownEvents:              generateEventsUniformDistribution([]int{4}, 120),
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleDownRules:               generateScalingRules(0, 0, 50, 180, 0),
			currentReplicas:              10,
			prenormalizedDesiredReplicas: 1,
			expectedReplicas:             6,
			expectedCondition:            "ScaleDownLimit",
		},
		{
			// corner case for calculating the scaleDownLimit, when we changed pod or percent policy after a lot of scaleDown events
			// in this case we shouldn't allow scale down, though, the naive formula will suggest that scaleDownlimit is more then CurrentReplicas (100+30-10% > 100)
			name:                         "scaleDown with previous events preventing further scale down",
			scaleDownEvents:              generateEventsUniformDistribution([]int{10, 10, 10}, 120),
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleDownRules:               generateScalingRules(0, 0, 10, 120, 300),
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 0,
			expectedReplicas:             100, // (100 + 30) - 10% = 117 is more then 100 (currentReplicas), keep 100
			expectedCondition:            "ScaleDownLimit",
		},
		{
			// corner case, the same as above, but calculation shows that we should go below zero
			name:                         "scaleDown with with previous events still allowing more scale down",
			scaleDownEvents:              generateEventsUniformDistribution([]int{10, 10, 10}, 120),
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleDownRules:               generateScalingRules(0, 0, 1000, 120, 300),
			currentReplicas:              10,
			prenormalizedDesiredReplicas: 5,
			expectedReplicas:             5, // (10 + 30) - 1000% = -360 is less than 0 and less then 5 (desired by metrics), set 5
			expectedCondition:            "DesiredWithinRange",
		},
		{
			name:                         "check 'outdated' flag for events for one behavior for up",
			scaleUpEvents:                generateEventsUniformDistribution([]int{8, 12, 9, 11}, 120),
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleUpRules:                 generateScalingRules(1000, 60, 0, 0, 0),
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 200,
			expectedReplicas:             200,
			expectedCondition:            "DesiredWithinRange",
		},
		{
			name:                         "check that events were not marked 'outdated' for two different policies in the behavior for up",
			scaleUpEvents:                generateEventsUniformDistribution([]int{8, 12, 9, 11}, 120),
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleUpRules:                 generateScalingRules(1000, 120, 100, 60, 0),
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 200,
			expectedReplicas:             200,
			expectedCondition:            "DesiredWithinRange",
		},
		{
			name:                         "check that events were marked 'outdated' for two different policies in the behavior for up",
			scaleUpEvents:                generateEventsUniformDistribution([]int{8, 12, 9, 11}, 120),
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleUpRules:                 generateScalingRules(1000, 30, 100, 60, 0),
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 200,
			expectedReplicas:             200,
			expectedCondition:            "DesiredWithinRange",
		},
		{
			name:                         "check 'outdated' flag for events for one behavior for down",
			scaleDownEvents:              generateEventsUniformDistribution([]int{8, 12, 9, 11}, 120),
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleDownRules:               generateScalingRules(1000, 60, 0, 0, 300),
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 5,
			expectedReplicas:             5,
			expectedCondition:            "DesiredWithinRange",
		},
		{
			name:                         "check that events were not marked 'outdated' for two different policies in the behavior for down",
			scaleDownEvents:              generateEventsUniformDistribution([]int{8, 12, 9, 11}, 120),
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleDownRules:               generateScalingRules(1000, 120, 100, 60, 300),
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 5,
			expectedReplicas:             5,
			expectedCondition:            "DesiredWithinRange",
		},
		{
			name:                         "check that events were marked 'outdated' for two different policies in the behavior for down",
			scaleDownEvents:              generateEventsUniformDistribution([]int{8, 12, 9, 11}, 120),
			specMinReplicas:              1,
			specMaxReplicas:              1000,
			scaleDownRules:               generateScalingRules(1000, 30, 100, 60, 300),
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 5,
			expectedReplicas:             5,
			expectedCondition:            "DesiredWithinRange",
		},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {

			if tc.testThis {
				return
			}
			hc := HorizontalController{
				scaleUpEvents: map[string][]timestampedScaleEvent{
					tc.key: tc.scaleUpEvents,
				},
				scaleDownEvents: map[string][]timestampedScaleEvent{
					tc.key: tc.scaleDownEvents,
				},
			}
			arg := NormalizationArg{
				Key:               tc.key,
				ScaleUpBehavior:   autoscalingapiv2.GenerateHPAScaleUpRules(tc.scaleUpRules),
				ScaleDownBehavior: autoscalingapiv2.GenerateHPAScaleDownRules(tc.scaleDownRules),
				MinReplicas:       tc.specMinReplicas,
				MaxReplicas:       tc.specMaxReplicas,
				DesiredReplicas:   tc.prenormalizedDesiredReplicas,
				CurrentReplicas:   tc.currentReplicas,
			}

			replicas, condition, _ := hc.convertDesiredReplicasWithBehaviorRate(arg)
			assert.Equal(t, tc.expectedReplicas, replicas, "expected replicas do not match with converted replicas")
			assert.Equal(t, tc.expectedCondition, condition, "HPA condition does not match with expected condition")
		})
	}

}

// TestStoreScaleEvents tests events storage and usage
func TestStoreScaleEvents(t *testing.T) {
	type TestCase struct {
		name                   string
		key                    string
		replicaChange          int32
		prevScaleEvents        []timestampedScaleEvent
		newScaleEvents         []timestampedScaleEvent
		scalingRules           *autoscalingv2.HPAScalingRules
		expectedReplicasChange int32
	}
	tests := []TestCase{
		{
			name:                   "empty entries with default behavior",
			replicaChange:          5,
			prevScaleEvents:        []timestampedScaleEvent{}, // no history -> 0 replica change
			newScaleEvents:         []timestampedScaleEvent{}, // no behavior -> no events are stored
			expectedReplicasChange: 0,
		},
		{
			name:                   "empty entries with two-policy-behavior",
			replicaChange:          5,
			prevScaleEvents:        []timestampedScaleEvent{}, // no history -> 0 replica change
			newScaleEvents:         []timestampedScaleEvent{{5, time.Now(), false}},
			scalingRules:           generateScalingRules(10, 60, 100, 60, 0),
			expectedReplicasChange: 0,
		},
		{
			name:          "one outdated entry to be kept untouched without behavior",
			replicaChange: 5,
			prevScaleEvents: []timestampedScaleEvent{
				{7, time.Now().Add(-time.Second * time.Duration(61)), false}, // outdated event, should be replaced
			},
			newScaleEvents: []timestampedScaleEvent{
				{7, time.Now(), false}, // no behavior -> we don't touch stored events
			},
			expectedReplicasChange: 0,
		},
		{
			name:          "one outdated entry to be replaced with behavior",
			replicaChange: 5,
			prevScaleEvents: []timestampedScaleEvent{
				{7, time.Now().Add(-time.Second * time.Duration(61)), false}, // outdated event, should be replaced
			},
			newScaleEvents: []timestampedScaleEvent{
				{5, time.Now(), false},
			},
			scalingRules:           generateScalingRules(10, 60, 100, 60, 0),
			expectedReplicasChange: 0,
		},
		{
			name:          "one actual entry to be not touched with behavior",
			replicaChange: 5,
			prevScaleEvents: []timestampedScaleEvent{
				{7, time.Now().Add(-time.Second * time.Duration(58)), false},
			},
			newScaleEvents: []timestampedScaleEvent{
				{7, time.Now(), false},
				{5, time.Now(), false},
			},
			scalingRules:           generateScalingRules(10, 60, 100, 60, 0),
			expectedReplicasChange: 7,
		},
		{
			name:          "two entries, one of them to be replaced",
			replicaChange: 5,
			prevScaleEvents: []timestampedScaleEvent{
				{7, time.Now().Add(-time.Second * time.Duration(61)), false}, // outdated event, should be replaced
				{6, time.Now().Add(-time.Second * time.Duration(59)), false},
			},
			newScaleEvents: []timestampedScaleEvent{
				{5, time.Now(), false},
				{6, time.Now(), false},
			},
			scalingRules:           generateScalingRules(10, 60, 0, 0, 0),
			expectedReplicasChange: 6,
		},
		{
			name:          "replace one entry, use policies with different periods",
			replicaChange: 5,
			prevScaleEvents: []timestampedScaleEvent{
				{8, time.Now().Add(-time.Second * time.Duration(29)), false},
				{6, time.Now().Add(-time.Second * time.Duration(59)), false},
				{7, time.Now().Add(-time.Second * time.Duration(61)), false}, // outdated event, should be marked as outdated
				{9, time.Now().Add(-time.Second * time.Duration(61)), false}, // outdated event, should be replaced
			},
			newScaleEvents: []timestampedScaleEvent{
				{8, time.Now(), false},
				{6, time.Now(), false},
				{7, time.Now(), true},
				{5, time.Now(), false},
			},
			scalingRules:           generateScalingRules(10, 60, 100, 30, 0),
			expectedReplicasChange: 14,
		},
		{
			name:          "two entries, both actual",
			replicaChange: 5,
			prevScaleEvents: []timestampedScaleEvent{
				{7, time.Now().Add(-time.Second * time.Duration(58)), false},
				{6, time.Now().Add(-time.Second * time.Duration(59)), false},
			},
			newScaleEvents: []timestampedScaleEvent{
				{7, time.Now(), false},
				{6, time.Now(), false},
				{5, time.Now(), false},
			},
			scalingRules:           generateScalingRules(10, 120, 100, 30, 0),
			expectedReplicasChange: 13,
		},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			// testing scale up
			var behaviorUp *autoscalingv2.HorizontalPodAutoscalerBehavior
			if tc.scalingRules != nil {
				behaviorUp = &autoscalingv2.HorizontalPodAutoscalerBehavior{
					ScaleUp: tc.scalingRules,
				}
			}
			hcUp := HorizontalController{
				scaleUpEvents: map[string][]timestampedScaleEvent{
					tc.key: append([]timestampedScaleEvent{}, tc.prevScaleEvents...),
				},
			}
			gotReplicasChangeUp := getReplicasChangePerPeriod(60, hcUp.scaleUpEvents[tc.key])
			assert.Equal(t, tc.expectedReplicasChange, gotReplicasChangeUp)
			hcUp.storeScaleEvent(behaviorUp, tc.key, 10, 10+tc.replicaChange)
			if !assert.Len(t, hcUp.scaleUpEvents[tc.key], len(tc.newScaleEvents), "up: scale events differ in length") {
				return
			}
			for i, gotEvent := range hcUp.scaleUpEvents[tc.key] {
				expEvent := tc.newScaleEvents[i]
				assert.Equal(t, expEvent.replicaChange, gotEvent.replicaChange, "up: idx:%v replicaChange", i)
				assert.Equal(t, expEvent.outdated, gotEvent.outdated, "up: idx:%v outdated", i)
			}
			// testing scale down
			var behaviorDown *autoscalingv2.HorizontalPodAutoscalerBehavior
			if tc.scalingRules != nil {
				behaviorDown = &autoscalingv2.HorizontalPodAutoscalerBehavior{
					ScaleDown: tc.scalingRules,
				}
			}
			hcDown := HorizontalController{
				scaleDownEvents: map[string][]timestampedScaleEvent{
					tc.key: append([]timestampedScaleEvent{}, tc.prevScaleEvents...),
				},
			}
			gotReplicasChangeDown := getReplicasChangePerPeriod(60, hcDown.scaleDownEvents[tc.key])
			assert.Equal(t, tc.expectedReplicasChange, gotReplicasChangeDown)
			hcDown.storeScaleEvent(behaviorDown, tc.key, 10, 10-tc.replicaChange)
			if !assert.Len(t, hcDown.scaleDownEvents[tc.key], len(tc.newScaleEvents), "down: scale events differ in length") {
				return
			}
			for i, gotEvent := range hcDown.scaleDownEvents[tc.key] {
				expEvent := tc.newScaleEvents[i]
				assert.Equal(t, expEvent.replicaChange, gotEvent.replicaChange, "down: idx:%v replicaChange", i)
				assert.Equal(t, expEvent.outdated, gotEvent.outdated, "down: idx:%v outdated", i)
			}
		})
	}
}

func TestNormalizeDesiredReplicasWithBehavior(t *testing.T) {
	now := time.Now()
	type TestCase struct {
		name                                string
		key                                 string
		recommendations                     []timestampedRecommendation
		currentReplicas                     int32
		prenormalizedDesiredReplicas        int32
		expectedStabilizedReplicas          int32
		expectedRecommendations             []timestampedRecommendation
		scaleUpStabilizationWindowSeconds   int32
		scaleDownStabilizationWindowSeconds int32
	}
	tests := []TestCase{
		{
			name:                         "empty recommendations for scaling down",
			key:                          "",
			recommendations:              []timestampedRecommendation{},
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 5,
			expectedStabilizedReplicas:   5,
			expectedRecommendations: []timestampedRecommendation{
				{5, now},
			},
		},
		{
			name: "simple scale down stabilization",
			key:  "",
			recommendations: []timestampedRecommendation{
				{4, now.Add(-2 * time.Minute)},
				{5, now.Add(-1 * time.Minute)}},
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 3,
			expectedStabilizedReplicas:   5,
			expectedRecommendations: []timestampedRecommendation{
				{4, now},
				{5, now},
				{3, now},
			},
			scaleDownStabilizationWindowSeconds: 60 * 3,
		},
		{
			name: "simple scale up stabilization",
			key:  "",
			recommendations: []timestampedRecommendation{
				{4, now.Add(-2 * time.Minute)},
				{5, now.Add(-1 * time.Minute)}},
			currentReplicas:              1,
			prenormalizedDesiredReplicas: 7,
			expectedStabilizedReplicas:   4,
			expectedRecommendations: []timestampedRecommendation{
				{4, now},
				{5, now},
				{7, now},
			},
			scaleUpStabilizationWindowSeconds: 60 * 5,
		},
		{
			name: "no scale down stabilization",
			key:  "",
			recommendations: []timestampedRecommendation{
				{1, now.Add(-2 * time.Minute)},
				{2, now.Add(-1 * time.Minute)}},
			currentReplicas:              100, // to apply scaleDown delay we should have current > desired
			prenormalizedDesiredReplicas: 3,
			expectedStabilizedReplicas:   3,
			expectedRecommendations: []timestampedRecommendation{
				{1, now},
				{2, now},
				{3, now},
			},
			scaleUpStabilizationWindowSeconds: 60 * 5,
		},
		{
			name: "no scale up stabilization",
			key:  "",
			recommendations: []timestampedRecommendation{
				{4, now.Add(-2 * time.Minute)},
				{5, now.Add(-1 * time.Minute)}},
			currentReplicas:              1, // to apply scaleDown delay we should have current > desired
			prenormalizedDesiredReplicas: 3,
			expectedStabilizedReplicas:   3,
			expectedRecommendations: []timestampedRecommendation{
				{4, now},
				{5, now},
				{3, now},
			},
			scaleDownStabilizationWindowSeconds: 60 * 5,
		},
		{
			name: "no scale down stabilization, reuse recommendation element",
			key:  "",
			recommendations: []timestampedRecommendation{
				{10, now.Add(-10 * time.Minute)},
				{9, now.Add(-9 * time.Minute)}},
			currentReplicas:              100, // to apply scaleDown delay we should have current > desired
			prenormalizedDesiredReplicas: 3,
			expectedStabilizedReplicas:   3,
			expectedRecommendations: []timestampedRecommendation{
				{10, now},
				{3, now},
			},
		},
		{
			name: "no scale up stabilization, reuse recommendation element",
			key:  "",
			recommendations: []timestampedRecommendation{
				{10, now.Add(-10 * time.Minute)},
				{9, now.Add(-9 * time.Minute)}},
			currentReplicas:              1,
			prenormalizedDesiredReplicas: 100,
			expectedStabilizedReplicas:   100,
			expectedRecommendations: []timestampedRecommendation{
				{10, now},
				{100, now},
			},
		},
		{
			name: "scale down stabilization, reuse one of obsolete recommendation element",
			key:  "",
			recommendations: []timestampedRecommendation{
				{10, now.Add(-10 * time.Minute)},
				{4, now.Add(-1 * time.Minute)},
				{5, now.Add(-2 * time.Minute)},
				{9, now.Add(-9 * time.Minute)}},
			currentReplicas:              100,
			prenormalizedDesiredReplicas: 3,
			expectedStabilizedReplicas:   5,
			expectedRecommendations: []timestampedRecommendation{
				{10, now},
				{4, now},
				{5, now},
				{3, now},
			},
			scaleDownStabilizationWindowSeconds: 3 * 60,
		},
		{
			// we can reuse only the first recommendation element
			// as the scale up delay = 150 (set in test), scale down delay = 300 (by default)
			// hence, only the first recommendation is obsolete for both scale up and scale down
			name: "scale up stabilization, reuse one of obsolete recommendation element",
			key:  "",
			recommendations: []timestampedRecommendation{
				{10, now.Add(-100 * time.Minute)},
				{6, now.Add(-1 * time.Minute)},
				{5, now.Add(-2 * time.Minute)},
				{9, now.Add(-3 * time.Minute)}},
			currentReplicas:              1,
			prenormalizedDesiredReplicas: 100,
			expectedStabilizedReplicas:   5,
			expectedRecommendations: []timestampedRecommendation{
				{100, now},
				{6, now},
				{5, now},
				{9, now},
			},
			scaleUpStabilizationWindowSeconds: 300,
		}, {
			name: "scale up and down stabilization, do not scale up when prenormalized rec goes down",
			key:  "",
			recommendations: []timestampedRecommendation{
				{2, now.Add(-100 * time.Minute)},
				{3, now.Add(-3 * time.Minute)},
			},
			currentReplicas:                     2,
			prenormalizedDesiredReplicas:        1,
			expectedStabilizedReplicas:          2,
			scaleUpStabilizationWindowSeconds:   300,
			scaleDownStabilizationWindowSeconds: 300,
		}, {
			name: "scale up and down stabilization, do not scale down when prenormalized rec goes up",
			key:  "",
			recommendations: []timestampedRecommendation{
				{2, now.Add(-100 * time.Minute)},
				{1, now.Add(-3 * time.Minute)},
			},
			currentReplicas:                     2,
			prenormalizedDesiredReplicas:        3,
			expectedStabilizedReplicas:          2,
			scaleUpStabilizationWindowSeconds:   300,
			scaleDownStabilizationWindowSeconds: 300,
		},
	}
	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			hc := HorizontalController{
				recommendations: map[string][]timestampedRecommendation{
					tc.key: tc.recommendations,
				},
			}
			arg := NormalizationArg{
				Key:             tc.key,
				DesiredReplicas: tc.prenormalizedDesiredReplicas,
				CurrentReplicas: tc.currentReplicas,
				ScaleUpBehavior: &autoscalingv2.HPAScalingRules{
					StabilizationWindowSeconds: &tc.scaleUpStabilizationWindowSeconds,
				},
				ScaleDownBehavior: &autoscalingv2.HPAScalingRules{
					StabilizationWindowSeconds: &tc.scaleDownStabilizationWindowSeconds,
				},
			}
			r, _, _ := hc.stabilizeRecommendationWithBehaviors(arg)
			assert.Equal(t, tc.expectedStabilizedReplicas, r, "expected replicas do not match")
			if tc.expectedRecommendations != nil {
				if !assert.Len(t, hc.recommendations[tc.key], len(tc.expectedRecommendations), "stored recommendations differ in length") {
					return
				}
				for i, r := range hc.recommendations[tc.key] {
					expectedRecommendation := tc.expectedRecommendations[i]
					assert.Equal(t, expectedRecommendation.recommendation, r.recommendation, "stored recommendation differs at position %d", i)
				}
			}
		})
	}
}

func TestScaleUpOneMetricEmpty(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 4,
		CPUTarget:               30,
		verifyCPUCurrent:        true,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.ExternalMetricSourceType,
				External: &autoscalingv2.ExternalMetricSource{
					Metric: autoscalingv2.MetricIdentifier{
						Name:     "qps",
						Selector: &metav1.LabelSelector{},
					},
					Target: autoscalingv2.MetricTarget{
						Type:  autoscalingv2.ValueMetricType,
						Value: resource.NewMilliQuantity(100, resource.DecimalSI),
					},
				},
			},
		},
		reportedLevels:      []uint64{300, 400, 500},
		reportedCPURequests: []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelInternal,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
			autoscalingv2.ExternalMetricSourceType: monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
			autoscalingv2.ExternalMetricSourceType: monitor.ErrorLabelInternal,
		},
	}
	_, _, _, testEMClient, _ := tc.prepareTestClient(t)
	testEMClient.PrependReactor("list", "*", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		return true, &emapi.ExternalMetricValueList{}, fmt.Errorf("something went wrong")
	})
	tc.testEMClient = testEMClient
	tc.runTest(t)
}

func TestNoScaleDownOneMetricInvalid(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            5,
		statusReplicas:          5,
		expectedDesiredReplicas: 5,
		CPUTarget:               50,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: "CheddarCheese",
			},
		},
		reportedLevels:      []uint64{100, 300, 500, 250, 250},
		reportedCPURequests: []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:       true,
		recommendations:     []timestampedRecommendation{},
		expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
			{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededGetScale"},
			{Type: autoscalingv2.ScalingActive, Status: v1.ConditionFalse, Reason: "InvalidMetricSourceType"},
		},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelInternal,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleDown,
			"CheddarCheese":                        monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
			"CheddarCheese":                        monitor.ErrorLabelSpec,
		},
	}

	tc.runTest(t)
}

func TestNoScaleDownOneMetricEmpty(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            5,
		statusReplicas:          5,
		expectedDesiredReplicas: 5,
		CPUTarget:               50,
		metricsTarget: []autoscalingv2.MetricSpec{
			{
				Type: autoscalingv2.ExternalMetricSourceType,
				External: &autoscalingv2.ExternalMetricSource{
					Metric: autoscalingv2.MetricIdentifier{
						Name:     "qps",
						Selector: &metav1.LabelSelector{},
					},
					Target: autoscalingv2.MetricTarget{
						Type:  autoscalingv2.ValueMetricType,
						Value: resource.NewMilliQuantity(1000, resource.DecimalSI),
					},
				},
			},
		},
		reportedLevels:      []uint64{100, 300, 500, 250, 250},
		reportedCPURequests: []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:       true,
		recommendations:     []timestampedRecommendation{},
		expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
			{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededGetScale"},
			{Type: autoscalingv2.ScalingActive, Status: v1.ConditionFalse, Reason: "FailedGetExternalMetric"},
		},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelInternal,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleDown,
			autoscalingv2.ExternalMetricSourceType: monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
			autoscalingv2.ExternalMetricSourceType: monitor.ErrorLabelInternal,
		},
	}
	_, _, _, testEMClient, _ := tc.prepareTestClient(t)
	testEMClient.PrependReactor("list", "*", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		return true, &emapi.ExternalMetricValueList{}, fmt.Errorf("something went wrong")
	})
	tc.testEMClient = testEMClient
	tc.runTest(t)
}

func TestMultipleHPAs(t *testing.T) {
	const hpaCount = 1000
	const testNamespace = "dummy-namespace"

	processed := make(chan string, hpaCount)

	testClient := &fake.Clientset{}
	testScaleClient := &scalefake.FakeScaleClient{}
	testMetricsClient := &metricsfake.Clientset{}
	hpaWatcher := watch.NewFake()
	podWatcher := watch.NewFake()

	testClient.AddWatchReactor("horizontalpodautoscalers", core.DefaultWatchReactor(hpaWatcher, nil))
	testClient.AddWatchReactor("pods", core.DefaultWatchReactor(podWatcher, nil))

	hpaList := [hpaCount]autoscalingv2.HorizontalPodAutoscaler{}
	scaleUpEventsMap := map[string][]timestampedScaleEvent{}
	scaleDownEventsMap := map[string][]timestampedScaleEvent{}
	scaleList := map[string]*autoscalingv1.Scale{}
	podList := map[string]*v1.Pod{}

	var minReplicas int32 = 1
	var cpuTarget int32 = 10

	// generate resources (HPAs, Scales, Pods...)
	for i := 0; i < hpaCount; i++ {
		hpaName := fmt.Sprintf("dummy-hpa-%v", i)
		deploymentName := fmt.Sprintf("dummy-target-%v", i)
		labelSet := map[string]string{"name": deploymentName}
		selector := labels.SelectorFromSet(labelSet).String()

		// generate HPAs
		h := autoscalingv2.HorizontalPodAutoscaler{
			ObjectMeta: metav1.ObjectMeta{
				Name:      hpaName,
				Namespace: testNamespace,
			},
			Spec: autoscalingv2.HorizontalPodAutoscalerSpec{
				ScaleTargetRef: autoscalingv2.CrossVersionObjectReference{
					APIVersion: "apps/v1",
					Kind:       "Deployment",
					Name:       deploymentName,
				},
				MinReplicas: &minReplicas,
				MaxReplicas: 10,
				Behavior: &autoscalingv2.HorizontalPodAutoscalerBehavior{
					ScaleUp:   generateScalingRules(100, 60, 0, 0, 0),
					ScaleDown: generateScalingRules(2, 60, 1, 60, 300),
				},
				Metrics: []autoscalingv2.MetricSpec{
					{
						Type: autoscalingv2.ResourceMetricSourceType,
						Resource: &autoscalingv2.ResourceMetricSource{
							Name: v1.ResourceCPU,
							Target: autoscalingv2.MetricTarget{
								Type:               autoscalingv2.UtilizationMetricType,
								AverageUtilization: &cpuTarget,
							},
						},
					},
				},
			},
			Status: autoscalingv2.HorizontalPodAutoscalerStatus{
				CurrentReplicas: 1,
				DesiredReplicas: 5,
				LastScaleTime:   &metav1.Time{Time: time.Now()},
			},
		}
		hpaList[i] = h

		// generate Scale
		scaleList[deploymentName] = &autoscalingv1.Scale{
			ObjectMeta: metav1.ObjectMeta{
				Name:      deploymentName,
				Namespace: testNamespace,
			},
			Spec: autoscalingv1.ScaleSpec{
				Replicas: 1,
			},
			Status: autoscalingv1.ScaleStatus{
				Replicas: 1,
				Selector: selector,
			},
		}

		// generate Pods
		cpuRequest := resource.MustParse("1.0")
		pod := v1.Pod{
			Status: v1.PodStatus{
				Phase: v1.PodRunning,
				Conditions: []v1.PodCondition{
					{
						Type:   v1.PodReady,
						Status: v1.ConditionTrue,
					},
				},
				StartTime: &metav1.Time{Time: time.Now().Add(-10 * time.Minute)},
			},
			ObjectMeta: metav1.ObjectMeta{
				Name:      fmt.Sprintf("%s-0", deploymentName),
				Namespace: testNamespace,
				Labels:    labelSet,
			},

			Spec: v1.PodSpec{
				Containers: []v1.Container{
					{
						Name: "container1",
						Resources: v1.ResourceRequirements{
							Requests: v1.ResourceList{
								v1.ResourceCPU: *resource.NewMilliQuantity(cpuRequest.MilliValue()/2, resource.DecimalSI),
							},
						},
					},
					{
						Name: "container2",
						Resources: v1.ResourceRequirements{
							Requests: v1.ResourceList{
								v1.ResourceCPU: *resource.NewMilliQuantity(cpuRequest.MilliValue()/2, resource.DecimalSI),
							},
						},
					},
				},
			},
		}
		podList[deploymentName] = &pod

		scaleUpEventsMap[fmt.Sprintf("%s/%s", testNamespace, hpaName)] = generateEventsUniformDistribution([]int{8, 12, 9, 11}, 120)
		scaleDownEventsMap[fmt.Sprintf("%s/%s", testNamespace, hpaName)] = generateEventsUniformDistribution([]int{10, 10, 10}, 120)
	}

	testMetricsClient.AddReactor("list", "pods", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		podNamePrefix := ""
		labelSet := map[string]string{}

		// selector should be in form: "name=dummy-target-X" where X is the number of resource
		selector := action.(core.ListAction).GetListRestrictions().Labels
		parsedSelector := strings.Split(selector.String(), "=")
		if len(parsedSelector) > 1 {
			labelSet[parsedSelector[0]] = parsedSelector[1]
			podNamePrefix = parsedSelector[1]
		}

		podMetric := metricsapi.PodMetrics{
			ObjectMeta: metav1.ObjectMeta{
				Name:      fmt.Sprintf("%s-0", podNamePrefix),
				Namespace: testNamespace,
				Labels:    labelSet,
			},
			Timestamp: metav1.Time{Time: time.Now()},
			Window:    metav1.Duration{Duration: time.Minute},
			Containers: []metricsapi.ContainerMetrics{
				{
					Name: "container1",
					Usage: v1.ResourceList{
						v1.ResourceCPU: *resource.NewMilliQuantity(
							int64(200),
							resource.DecimalSI),
						v1.ResourceMemory: *resource.NewQuantity(
							int64(1024*1024/2),
							resource.BinarySI),
					},
				},
				{
					Name: "container2",
					Usage: v1.ResourceList{
						v1.ResourceCPU: *resource.NewMilliQuantity(
							int64(300),
							resource.DecimalSI),
						v1.ResourceMemory: *resource.NewQuantity(
							int64(1024*1024/2),
							resource.BinarySI),
					},
				},
			},
		}
		metrics := &metricsapi.PodMetricsList{}
		metrics.Items = append(metrics.Items, podMetric)

		return true, metrics, nil
	})

	metricsClient := metrics.NewRESTMetricsClient(
		testMetricsClient.MetricsV1beta1(),
		&cmfake.FakeCustomMetricsClient{},
		&emfake.FakeExternalMetricsClient{},
	)

	testScaleClient.AddReactor("get", "deployments", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		deploymentName := action.(core.GetAction).GetName()
		obj := scaleList[deploymentName]
		return true, obj, nil
	})

	testClient.AddReactor("list", "pods", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		obj := &v1.PodList{}

		// selector should be in form: "name=dummy-target-X" where X is the number of resource
		selector := action.(core.ListAction).GetListRestrictions().Labels
		parsedSelector := strings.Split(selector.String(), "=")

		// list with filter
		if len(parsedSelector) > 1 {
			obj.Items = append(obj.Items, *podList[parsedSelector[1]])
		} else {
			// no filter - return all pods
			for _, p := range podList {
				obj.Items = append(obj.Items, *p)
			}
		}

		return true, obj, nil
	})

	testClient.AddReactor("list", "horizontalpodautoscalers", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		obj := &autoscalingv2.HorizontalPodAutoscalerList{
			Items: hpaList[:],
		}
		return true, obj, nil
	})

	testClient.AddReactor("update", "horizontalpodautoscalers", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		handled, obj, err := func() (handled bool, ret *autoscalingv2.HorizontalPodAutoscaler, err error) {
			obj := action.(core.UpdateAction).GetObject().(*autoscalingv2.HorizontalPodAutoscaler)
			assert.Equal(t, testNamespace, obj.Namespace, "the HPA namespace should be as expected")

			return true, obj, nil
		}()
		processed <- obj.Name

		return handled, obj, err
	})

	informerFactory := informers.NewSharedInformerFactory(testClient, controller.NoResyncPeriodFunc())

	tCtx := ktesting.Init(t)
	hpaController := NewHorizontalController(
		tCtx,
		testClient.CoreV1(),
		testScaleClient,
		testClient.AutoscalingV2(),
		testrestmapper.TestOnlyStaticRESTMapper(legacyscheme.Scheme),
		metricsClient,
		informerFactory.Autoscaling().V2().HorizontalPodAutoscalers(),
		informerFactory.Core().V1().Pods(),
		100*time.Millisecond,
		5*time.Minute,
		defaultTestingTolerance,
		defaultTestingCPUInitializationPeriod,
		defaultTestingDelayOfInitialReadinessStatus,
	)
	hpaController.scaleUpEvents = scaleUpEventsMap
	hpaController.scaleDownEvents = scaleDownEventsMap
	monitor.Register()
	monitor.NumHorizontalPodAutoscalers.Set(0)
	hpaController.monitor = monitor.New()

	informerFactory.Start(tCtx.Done())
	go hpaController.Run(tCtx, 5)

	timeoutTime := time.After(15 * time.Second)
	timeout := false
	processedHPA := make(map[string]bool)
	for timeout == false && len(processedHPA) < hpaCount {
		select {
		case hpaName := <-processed:
			processedHPA[hpaName] = true
		case <-timeoutTime:
			timeout = true
		}
	}

	assert.Len(t, processedHPA, hpaCount, "Expected to process all HPAs")
	v, err := metricstestutil.GetGaugeMetricValue(monitor.NumHorizontalPodAutoscalers)
	require.NoError(t, err)
	assert.InEpsilon(t, float64(hpaCount), v, 0.01, "Expected objects count to match number of HPAs")

	// Simulate the watch event for deletion
	hpaWatcher.Delete(&hpaList[0])

	// Give the controller time to process the deletion and update the monitor
	assert.Eventually(t, func() bool {
		v, err := metricstestutil.GetGaugeMetricValue(monitor.NumHorizontalPodAutoscalers)
		return err == nil && v == float64(hpaCount-1)
	}, 5*time.Second, 100*time.Millisecond, "Expected objects count to be hpaCount-1 after an HPA was deleted")
}

func TestHPARescaleWithSuccessfulConflictRetry(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 5, // On success, the desired count is updated.
		CPUTarget:               50,
		reportedLevels:          []uint64{600, 700, 800},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:           true,
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "SucceededRescale",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
	}

	_, _, _, _, testScaleClient := tc.prepareTestClient(t)
	tc.testScaleClient = testScaleClient

	updateCallCount := 0
	// Use PrependReactor to simulate a transient conflict.
	testScaleClient.PrependReactor("update", "replicationcontrollers", func(action core.Action) (handled bool, ret runtime.Object, err error) {
		updateCallCount++
		// On the first call, simulate a conflict error.
		if updateCallCount == 1 {
			return true, nil, k8serrors.NewConflict(schema.GroupResource{Group: "", Resource: "replicationcontrollers"}, "test-rc", fmt.Errorf("simulated conflict"))
		}
		// On subsequent calls, let the default successful reactor handle it.
		return false, nil, nil
	})

	tc.runTest(t)
}

func TestReconciliationDurationIsRecorded(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 5,
		CPUTarget:               30,
		verifyCPUCurrent:        true,
		reportedLevels:          []uint64{300, 500, 700},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:           true,
		expectedReportedReconciliationActionLabel: monitor.ActionLabelScaleUp,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelScaleUp,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
		verifyReconciliationDuration:     true,
		verifyMetricComputationDurations: true,
	}
	tc.runTest(t)
}

func TestReconciliationDurationIsRecordedOnError(t *testing.T) {
	tc := testCase{
		minReplicas:             2,
		maxReplicas:             6,
		specReplicas:            4,
		statusReplicas:          4,
		expectedDesiredReplicas: 4,
		CPUTarget:               100,
		reportedLevels:          []uint64{},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0"), resource.MustParse("1.0")},
		useMetricsAPI:           true,
		expectedConditions: []autoscalingv2.HorizontalPodAutoscalerCondition{
			{Type: autoscalingv2.AbleToScale, Status: v1.ConditionTrue, Reason: "SucceededGetScale"},
			{Type: autoscalingv2.ScalingActive, Status: v1.ConditionFalse, Reason: "FailedGetResourceMetric"},
		},
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelInternal,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelInternal,
		},
		verifyReconciliationDuration:     true,
		verifyMetricComputationDurations: true,
	}
	tc.runTest(t)
}

func TestReconciliationsTotalCountMultipleReconciliations(t *testing.T) {
	tc := testCase{
		minReplicas:             1,
		maxReplicas:             5,
		specReplicas:            3,
		statusReplicas:          3,
		expectedDesiredReplicas: 3,
		CPUTarget:               100,
		reportedLevels:          []uint64{1010, 1030, 1020},
		reportedCPURequests:     []resource.Quantity{resource.MustParse("0.9"), resource.MustParse("1.0"), resource.MustParse("1.1")},
		useMetricsAPI:           true,
		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
			Type:   autoscalingv2.AbleToScale,
			Status: v1.ConditionTrue,
			Reason: "ReadyForNewScale",
		}),
		expectedReportedReconciliationActionLabel: monitor.ActionLabelNone,
		expectedReportedReconciliationErrorLabel:  monitor.ErrorLabelNone,
		expectedReportedMetricComputationActionLabels: map[autoscalingv2.MetricSourceType]monitor.ActionLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ActionLabelNone,
		},
		expectedReportedMetricComputationErrorLabels: map[autoscalingv2.MetricSourceType]monitor.ErrorLabel{
			autoscalingv2.ResourceMetricSourceType: monitor.ErrorLabelNone,
		},
		// The specific count value is not important. This test verifies that
		// reconciliationsTotal counter is incremented on each reconciliation cycle.
		expectedReconciliationCount: 3,
		// The specific count values are not important. This test verifies that
		// metricComputationTotal counter is incremented for each metric type on each reconciliation.
		expectedMetricComputationCounts: map[autoscalingv2.MetricSourceType]int{
			autoscalingv2.ResourceMetricSourceType: 3,
		},
	}
	tc.runTest(t)
}

func TestBuildQuantity(t *testing.T) {
	tests := []struct {
		name         string
		resourceName v1.ResourceName
		rawProposal  int64
		expected     resource.Quantity
	}{
		{
			name:         "Memory - 1000 bytes → 1Ki",
			resourceName: v1.ResourceMemory,
			rawProposal:  1000,
			expected:     *resource.NewQuantity(1, resource.BinarySI), // 1Ki
		},
		{
			name:         "Memory - 1000000 bytes → 1000Ki",
			resourceName: v1.ResourceMemory,
			rawProposal:  1000000,
			expected:     *resource.NewQuantity(1000, resource.BinarySI), // 1000Ki
		},
		{
			name:         "CPU - 100 milli-cores",
			resourceName: v1.ResourceCPU,
			rawProposal:  100,
			expected:     *resource.NewMilliQuantity(100, resource.DecimalSI),
		},
		{
			name:         "CPU - 500 milli-cores",
			resourceName: v1.ResourceCPU,
			rawProposal:  500,
			expected:     *resource.NewMilliQuantity(500, resource.DecimalSI),
		},
		{
			name:         "CPU - 1 milli-core",
			resourceName: v1.ResourceCPU,
			rawProposal:  1,
			expected:     *resource.NewMilliQuantity(1, resource.DecimalSI),
		},
		{
			name:         "CustomResource - 200 milli-units",
			resourceName: v1.ResourceName("custom-resource"),
			rawProposal:  200,
			expected:     *resource.NewMilliQuantity(200, resource.DecimalSI),
		},
		{
			name:         "CustomResource - 300 milli-units",
			resourceName: v1.ResourceName("custom-resource"),
			rawProposal:  300,
			expected:     *resource.NewMilliQuantity(300, resource.DecimalSI),
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			q := buildQuantity(tt.resourceName, tt.rawProposal)
			if !q.Equal(tt.expected) || (q.Format != tt.expected.Format) {
				t.Errorf("expected quantity %v (Format: %v), got %v (Format: %v)",
					tt.expected.String(), tt.expected.Format,
					q.String(), q.Format)
			}
		})
	}
}
