'Check that various Nonexistent/invalid keys give 404 errors'

@ddt.data('library-v1:Nonexistent+library', 'course-v1:Org+Course', 'course-v1:Org+Course+Run', 'invalid')
def test_invalid_keys(self, key_str):

    response = self.client.get_json(make_url_for_lib(key_str))
    self.assertEqual(response.status_code, 404)
