These tests look much better, but I think they could still be improved a little bit. My rule of thumb is basically trying to read the test name (e.g. `TestIntValidator.test_int_unchanged`) and try to read it out loud and understand what it does.

To make it clearer, I would change it to something like `test_it_returns_the_parameter_unchanged_if_it_was_an_int`. Another example would be `test_string_with_whitespace_converted` would become `test_it_converts_string_with_whitespace`.

This creates big test methods' names, but it makes them easier to read IMO. Your tests are really simple, so it's not such a big difference here. It's more just to keep the pattern so others reading your code will try to follow it.