A few tests fail in the coverage Travis target (see e.g. https://travis-ci.org/python/cpython/jobs/206480468): test_traceback and test_xml_etree.

I extracted the actual failures by running in verbose mode locally:

======================================================================
FAIL: test_recursive_traceback_cpython_internal (test.test_traceback.TracebackFormatTests)
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Traceback (most recent call last):
  File "/home/jelle/cpython-dev/cpython-1/Lib/test/test_traceback.py", line 431, in test_recursive_traceback_cpython_internal
    self._check_recursive_traceback_display(render_exc)
  File "/home/jelle/cpython-dev/cpython-1/Lib/test/test_traceback.py", line 347, in _check_recursive_traceback_display
    self.assertEqual(actual[-1], expected[-1])
AssertionError: 'RecursionError: maximum recursion depth exceeded in comparison' != 'RecursionError: maximum recursion depth exceeded'
- RecursionError: maximum recursion depth exceeded in comparison
?                                                 --------------
+ RecursionError: maximum recursion depth exceeded


======================================================================
FAIL: test_recursive_traceback_python (test.test_traceback.TracebackFormatTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/jelle/cpython-dev/cpython-1/Lib/test/test_traceback.py", line 423, in test_recursive_traceback_python
    self._check_recursive_traceback_display(traceback.print_exc)
  File "/home/jelle/cpython-dev/cpython-1/Lib/test/test_traceback.py", line 347, in _check_recursive_traceback_display
    self.assertEqual(actual[-1], expected[-1])
AssertionError: 'RecursionError: maximum recursion depth exceeded in comparison' != 'RecursionError: maximum recursion depth exceeded'
- RecursionError: maximum recursion depth exceeded in comparison
?                                                 --------------
+ RecursionError: maximum recursion depth exceeded



======================================================================
FAIL: test_bug_xmltoolkit63 (test.test_xml_etree.BugsTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/jelle/cpython-dev/cpython-1/Lib/test/test_xml_etree.py", line 1538, in test_bug_xmltoolkit63
    self.assertEqual(sys.getrefcount(None), count)
AssertionError: 505087 != 505084


Fixing this will improve the coverage check on PRs.