def test_readAll(self):
        """
        Calling L{_InputStream.read} with no arguments returns the entire input
        stream.
        """
        bytes = b"some bytes are here"
        d = self._renderAndReturnReaderResult(lambda input: input.read(), bytes)
        d.addCallback(self.assertEqual, bytes)
        return d

        Calling L{_InputStream.read} with no arguments returns the entire input
        stream.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_wsgi.py