def test_invalidStartBytePos(self):
        """
        If a range is unsatisfiable due to the start not being less than the
        length of the resource, the response is 416 (Requested range not
        satisfiable) and no data is written to the response body (RFC 2616,
        section 14.35.1).
        """
        self.request.requestHeaders.addRawHeader(b'range', b'bytes=67-108')
        self.resource.render(self.request)
        self.assertEqual(
            self.request.responseCode, http.REQUESTED_RANGE_NOT_SATISFIABLE)
        self.assertEqual(b''.join(self.request.written), b'')
        self.assertEqual(
            self.request.responseHeaders.getRawHeaders(b'content-length')[0],
            b'0')
        # Sections 10.4.17 and 14.16
        self.assertEqual(
            self.request.responseHeaders.getRawHeaders(b'content-range')[0],
            networkString('bytes */%d' % (len(self.payload),)))

        If a range is unsatisfiable due to the start not being less than the
        length of the resource, the response is 416 (Requested range not
        satisfiable) and no data is written to the response body (RFC 2616,
        section 14.35.1).
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_static.py