def test_hasHeaderTrue(self):
        """
        Check that L{Headers.hasHeader} returns C{True} when the given header
        is found.
        """
        h = Headers()
        h.setRawHeaders(u"test\u00E1", [u"lemur"])
        self.assertTrue(h.hasHeader(u"test\u00E1"))
        self.assertTrue(h.hasHeader(u"Test\u00E1"))
        self.assertTrue(h.hasHeader(b"test\xe1"))
        self.assertTrue(h.hasHeader(b"Test\xe1"))

        Check that L{Headers.hasHeader} returns C{True} when the given header
        is found.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_http_headers.py