> pytest fixtures don't have that issue, as they're only run when you include the fixture for DI

I don't see how that prevents any of the basic problems raised in the article.

py.test avoids XUnit or unittest style class-based tests for this reason (though it will run them if you insist). It opts for simple test functions instead. Fixtures are passed in explicitly as parameters rather than implicitly as class members or whatnot. The result of all this is quite similar to what the author proposes.