Use assertIs(Not)None to check for None

[H203] Use assertIs(Not)None to check for None (off by default) Unit
test assertions tend to give better messages for more specific
assertions. As a result, assertIsNone(...) is preferred over
assertEqual(None, ...) and assertIs(None, ...), and assertIsNotNone(...)
is preferred over assertNotEqual(None, ...) and assertIsNot(None,
...). Off by default.

More information, see:
http://docs.openstack.org/developer/hacking/#unit-tests-and-assertraises

Change-Id: I73a9ed3e145b8f36c110725d148baf1fb0aef957
1 file changed