\documentclass{article}
\usepackage{graphicx}
\begin{document}

\begin{figure}
\includegraphics{fig_testb.pdf}
\end{figure}

\begin{figure}
\includegraphics{fig_testc.pdf}
\end{figure}

Figure tests \verb#\includegraphic{fig_testb.pdf}#.  This cannot be in
\texttt{fig\_test.tex} because that file needs to be run through \LaTeX\
so that the cross-references can be determined.  The problem with
that is that \LaTeX\ does not handle \texttt{.pdf} files.  

\end{document}
