'L{SSHUserAuthClient} looks up public keys from the agent using the
L{SSHAgentClient} class.  That L{SSHAgentClient.getPublicKey} returns a
L{Key} object with one of the public keys in the agent.  If no more
keys are present, it returns L{None}.'

def test_agentGetPublicKey(self):

    agent = SSHAgentClient()
    agent.blobs = [self.rsaPublic.blob()]
    key = agent.getPublicKey()
    self.assertTrue(key.isPublic())
    self.assertEqual(key, self.rsaPublic)
    self.assertIsNone(agent.getPublicKey())
