* Mark functions that will never be called with # pragma: no cover
* Fix testpatch.PatchTest.test_exit_idempotent
.stop() and __exit__ have subtly different code paths, so to really test __exit__ idempotency, we need to call it specifically twice.
Add the following methods:
* assertHasAttr() and assertNotHasAttr()
* assertIsSubclass() and assertNotIsSubclass()
* assertStartsWith() and assertNotStartsWith()
* assertEndsWith() and assertNotEndsWith()
Also improve error messages for assertIsInstance() and
assertNotIsInstance().
Fixes unittest.mock.patch not enforcing function signatures for methods
decorated with @classmethod or @staticmethod when patch is called with
autospec=True.
Chris Withers