def test_shortStrings(self):
        """
        If L{_IdentityTransferDecoder.dataReceived} is called multiple times
        with byte strings which, when concatenated, are as long as the content
        length provided, the data callback is invoked with each string and the
        finish callback is invoked only after the second call.
        """
        self.decoder.dataReceived(b'x')
        self.assertEqual(self.data, [b'x'])
        self.assertEqual(self.finish, [])
        self.decoder.dataReceived(b'y' * (self.contentLength - 1))
        self.assertEqual(self.data, [b'x', b'y' * (self.contentLength - 1)])
        self.assertEqual(self.finish, [b''])

        If L{_IdentityTransferDecoder.dataReceived} is called multiple times
        with byte strings which, when concatenated, are as long as the content
        length provided, the data callback is invoked with each string and the
        finish callback is invoked only after the second call.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_http.py