def test_resumeProducingProducesContent(self):
        """
        L{SingleRangeStaticProducer.resumeProducing} writes the given amount
        of content, starting at the given offset, from the resource to the
        request.
        """
        request = DummyRequest([])
        content = b'abcdef'
        producer = static.SingleRangeStaticProducer(
            request, StringIO(content), 1, 3)
        # DummyRequest.registerProducer pulls all output from the producer, so
        # we just need to call start.
        producer.start()
        self.assertEqual(content[1:4], b''.join(request.written))

        L{SingleRangeStaticProducer.resumeProducing} writes the given amount
        of content, starting at the given offset, from the resource to the
        request.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_static.py