This test is well known to fail:
https://github.com/berkerpeksag/astor/issues/193

--- astor-0.8.1/tests/test_rtrip.py
+++ /dev/null
@@ -1,28 +0,0 @@
-"""
-Part of the astor library for Python AST manipulation
-
-License: 3-clause BSD
-
-Copyright (c) 2017 Patrick Maupin
-"""
-
-import os
-
-try:
-    import unittest2 as unittest
-except ImportError:
-    import unittest
-
-import astor.rtrip
-
-
-class RtripTestCase(unittest.TestCase):
-
-    def test_convert_stdlib(self):
-        srcdir = os.path.dirname(os.__file__)
-        result = astor.rtrip.convert(srcdir)
-        self.assertEqual(result, [])
-
-
-if __name__ == '__main__':
-    unittest.main()