I don't know how it works on other platforms but test_get_python_inc is incorrect when run, as in this case, from a user-installed python rather than as part of a build of python. The relevant code in test_sysconfig.py: >>> (srcdir,) = sysconfig.get_config_vars('srcdir') >>> srcdir '/Users/ronald/Projects/python/r263' >>> inc_dir = sysconfig.get_python_inc() >>> inc_dir '/Library/Frameworks/Python.framework/Versions/2.6/include/python2.6' That's where Python.h exists in an OS X framework install. The srcdir captured is useless on other than the build machine; there is none. (People who build OS X python installers don't see this problem when they run the tests on a machine which happens to have a build directory in the same location.)
