+Coverage works pretty well, but occasionally things don't go as you would like.
+This page details problems, with links to coverage.py bug reports if
+You can of course search the `coverage.py bug tracker`_ directly to see if
+there is some mention of your problem.
+.. _coverage.py bug tracker: https://bitbucket.org/ned/coveragepy/issues?status=new&status=open
+There are a number of popular packages that prevent coverage.py from working
+* execv, or one of its variants, `issue 43`_.
+* multiprocessing, `issue 117`_.
+Code is marked as not executed when I know it is.
+link to DecoratorTools, TurboGears
+.. _issue 43: https://bitbucket.org/ned/coveragepy/issue/43/coverage-measurement-fails-on-code
+.. _issue 117: https://bitbucket.org/ned/coveragepy/issue/117/enable-coverage-measurement-of-code-run-by
+.. _issue 149: https://bitbucket.org/ned/coveragepy/issue/149/coverage-gevent-looks-broken
+* Python 2.5 had a bug (`1569356`_) that could make your program behave
+ differently when being measured with coverage. This is diagnosed in `issue 51`_.
+.. _issue 51: http://bitbucket.org/ned/coveragepy/issue/51/turbogears-15-test-failing-with-coverage
+.. _1569356: http://bugs.python.org/issue1569356