'If the running ssh-agent has the provided private key, then
``ssh_agent_has_ssh_key`` returns a successful deferred.'

def test_private_key_in_agent(self):

    key_file = FilePath(self.mktemp())
    key = generate_ssh_key(key_file)
    create_ssh_agent(key_file, self)
    result = ensure_agent_has_ssh_key(self.reactor, key)
    return result
