'Information updates from a source with no activity for more than the
hard-coded expiration period are wiped.'

def test_expiration_from_inactivity(self):

    service = self.service()
    source = ChangeSource()
    source.set_last_activity(self.clock.seconds())
    service.apply_changes_from_source(source, [self.WITH_APPS])
    advance_some(self.clock)
    source.set_last_activity(self.clock.seconds())
    advance_rest(self.clock)
    before_wipe_state = service.as_deployment()
    advance_some(self.clock)
    after_wipe_state = service.as_deployment()
    self.assertEqual([before_wipe_state, after_wipe_state], [DeploymentState(nodes=[self.WITH_APPS]), DeploymentState()])
