The unittest documentation, argument names and implementation need to be consistent about the order of (actual, expected) for TestCase.assert methods that take two arguments. 

This is particularly relevant for the methods that produce 'diffed' output on failure - as the order determines whether mismatched items are missing from the expected or additional to the expected.

The documentation, signatures and implementation of all two argument asserts need to be checked to ensure they are the same and implemented correctly.

Personally I prefer (actual, expected).