def test_channel_request_no_messages(self):
    environ = _build_poll_environ('id')
    expected_headers = {
        'Cache-Control': 'no-cache',
        'Content-Length': '0',
    }
    self.assertResponse('200 OK', expected_headers, '', channel.application,
                        environ)
Evaluate a PEP 426 environment marker using markerlib.
dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/tools/devappserver2/channel_test.py/DevAppserverChannelTest.test_channel_request_no_messages--crossover with--dataset/ETHPy150Open anzev/hedwig/build/pip/pip/_vendor/pkg_resources/__init__.py/MarkerEvaluation._markerlib_evaluate