def test_getAllHeaders(self):
        """
        L{http.Request.getAllheaders} returns a C{dict} mapping all request
        header names to their corresponding values.
        """
        req = http.Request(DummyChannel(), False)
        req.requestHeaders.setRawHeaders(b"test", [b"lemur"])
        self.assertEqual(req.getAllHeaders(), {b"test": b"lemur"})

        L{http.Request.getAllheaders} returns a C{dict} mapping all request
        header names to their corresponding values.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_http.py