importlib.test.support to importlib.test.source.util.
case-insensitive file system, leading to test failures. This was due to using the TestCase objects directly instead of the guard in the test_main() function. Move over to a class decorator instead to control if the tests should be run.
planned for the package. There are no docs yet, but they are coming once the API for the first new function, importlib.import_module() is finalized.