def test_verifyNonPresentECKey(self):
        """
        Set up a test to verify an ECDSA key that isn't present.
        Return a 3-tuple of the UI, a list set up to collect the result
        of the verifyHostKey call, and the sample L{KnownHostsFile} being used.
        """
        ecObj = Key._fromECComponents(
            x=keydata.ECDatanistp256['x'],
            y=keydata.ECDatanistp256['y'],
            privateValue=keydata.ECDatanistp256['privateValue'],
            curve=keydata.ECDatanistp256['curve']
        )

        hostsFile = self.loadSampleHostsFile()
        ui = FakeUI()
        l = []
        d = hostsFile.verifyHostKey(
            ui, b"sample-host.example.com", b"4.3.2.1", ecObj)
        d.addBoth(l.append)
        self.assertEqual([], l)
        self.assertEqual(
            ui.promptText,
            b"The authenticity of host 'sample-host.example.com (4.3.2.1)' "
            b"can't be established.\n"
            b"ECDSA key fingerprint is "
            b"SHA256:fJnSpgCcYoYYsaBbnWj1YBghGh/QTDgfe4w4U5M5tEo=.\n"
            b"Are you sure you want to continue connecting (yes/no)? ")

        Set up a test to verify an ECDSA key that isn't present.
        Return a 3-tuple of the UI, a list set up to collect the result
        of the verifyHostKey call, and the sample L{KnownHostsFile} being used.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_knownhosts.py