Merge in recent changes from development branch: add warning about being

sure that code only runs once when using the module as both a module and a
script.

diff --git a/Doc/lib/libdoctest.tex b/Doc/lib/libdoctest.tex
index 6d19259d257eafc0f8dbb5509b74a0712277be17..9b99b9d51d25f888c51b958dbb96d2d1c3d4f6e6 100644 (file)
--- a/Doc/lib/libdoctest.tex
+++ b/Doc/lib/libdoctest.tex
@@ -406,6 +406,17 @@ often contrive doctest examples to produce numbers of that form:
 
 Simple fractions are also easier for people to understand, and that makes
 for better documentation.
+
+\item Be careful if you have code that must only execute once.
+
+If you have module-level code that must only execute once, a more foolproof
+definition of \function{_test()} is
+
+\begin{verbatim}
+def _test():
+    import doctest, sys
+    doctest.testmod(sys.modules["__main__"])
+\end{verbatim}
 \end{enumerate}