def test_readSome(self):
        """
        Calling L{_InputStream.read} with an integer returns that many bytes
        from the input stream, as long as it is less than or equal to the total
        number of bytes available.
        """
        bytes = b"hello, world."
        d = self._renderAndReturnReaderResult(lambda input: input.read(3), bytes)
        d.addCallback(self.assertEqual, b"hel")
        return d

        Calling L{_InputStream.read} with an integer returns that many bytes
        from the input stream, as long as it is less than or equal to the total
        number of bytes available.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_wsgi.py