def test_tlsAfterStartTLS(self):
        """
        The C{TLS} attribute of a L{Connection} instance is C{True} after
        L{Connection.startTLS} is called.
        """
        skt = FakeSocket(b"")
        protocol = FakeProtocol()
        conn = Connection(skt, protocol, reactor=_FakeFDSetReactor())
        conn._tlsClientDefault = True
        conn.startTLS(ClientContextFactory(), True)
        self.assertTrue(conn.TLS)

        The C{TLS} attribute of a L{Connection} instance is C{True} after
        L{Connection.startTLS} is called.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_tcp.py