Don't use os.normcase when the result we are expecting is None.
This worked fine on linux but fails on Windows. That may or may
not be a but in normcase.
diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
index b515c1f..08e5022 100644
--- a/Lib/test/test_inspect.py
+++ b/Lib/test/test_inspect.py
@@ -278,7 +278,7 @@
self.assertEqual(normcase(inspect.getsourcefile(git.abuse)), modfile)
fn = "_non_existing_filename_used_for_sourcefile_test.py"
co = compile("None", fn, "exec")
- self.assertEqual(normcase(inspect.getsourcefile(co)), None)
+ self.assertEqual(inspect.getsourcefile(co), None)
linecache.cache[co.co_filename] = (1, None, "None", co.co_filename)
self.assertEqual(normcase(inspect.getsourcefile(co)), fn)