'Verifying a valid key should return a L{Deferred} which fires with
True.'

def test_verifyValidKey(self):

    hostsFile = self.loadSampleHostsFile()
    hostsFile.addHostKey('1.2.3.4', Key.fromString(sampleKey))
    ui = FakeUI()
    d = hostsFile.verifyHostKey(ui, 'www.twistedmatrix.com', '1.2.3.4', Key.fromString(sampleKey))
    l = []
    d.addCallback(l.append)
    self.assertEqual(l, [True])
