'If ``WSGI_APPLICATION`` is ``None``, the return value of
``get_wsgi_application`` is returned.'

@override_settings(WSGI_APPLICATION=None)
def test_default(self):

    fake_app = object()
    def mock_get_wsgi_app():
        return fake_app
    from django.core.servers import basehttp
    _orig_get_wsgi_app = basehttp.get_wsgi_application
    basehttp.get_wsgi_application = mock_get_wsgi_app
    try:
        app = get_internal_wsgi_application()
        self.assertIs(app, fake_app)
    finally:
        basehttp.get_wsgi_application = _orig_get_wsgi_app
