test_support fails in my environment, only when run from an installed Python, due to permissions issues:

======================================================================
ERROR: test_forget (test.test_support.TestSupport)
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Traceback (most recent call last):
  File "/usr/local/lib/python3.3/test/test_support.py", line 59, in test_forget
    support.forget("smtplib")
  File "/usr/local/lib/python3.3/test/support.py", line 248, in forget
    unlink(imp.cache_from_source(source, debug_override=True))
  File "/usr/local/lib/python3.3/test/support.py", line 205, in unlink
    os.unlink(filename)
OSError: [Errno 13] Permission denied: '/usr/local/lib/python3.3/__pycache__/smtplib.cpython-33.pyc'

The issue is similar to #12331, which was recently fixed.