I am pretty much sure thattest_pickle.test_complete does nothing.
Evidences:

• After runningpython tests.py matplotlib.tests.test_pickle there is noresult_images folder
• This test passes even with addingassert False to the top of the function

This behavior is caused by using simultaneously thecleanup andimage_comparison decorators.
I suggest removing thecleanup decorator and regenerate baseline image (PR#6840).

The bug comes fromd595fe3 (PR#4264)