We do not usually make pure style changes in a file unless the code is being reviewed and edited. Even then, I focus on changes that make the file easier to read and understand, as is necessary to write tests. One example is adding missing spaces after commas in function definitions and calls (not a problem in this file, as far as I see). Another is to add PEP8 style docstrings to document the behavior being tested. That is an issue for this file. The name clashes do not bother me: 'file' is no longer a builtin in 3.x; 'sorted' was used in the file before the builtin was added (though I might think of something different if I were writing today). So lets leave the names alone and focus on good docstrings.