App Engine Unit Testing: ImportError: Start directory is not importable

Here, "test path" should be a directory that contains the tests you want to run, not the path to a single module. Try just using . as the directory (assuming you're running it from the top-level project/app directory) and see if that helps.

My team keeps our tests in a separate directory from our source code, so we would use a path to our test directory as that second argument.