'If the era differs the corresponding ``NodeState`` is removed.'

def test_different_era_discards_state(self):

    state = self.UPDATE_ERA_1.update_cluster_state(self.INITIAL_CLUSTER)
    state = self.NODE_STATE.update_cluster_state(state)
    updated_state = self.UPDATE_ERA_2.update_cluster_state(state)
    self.assertEqual(updated_state, self.UPDATE_ERA_2.update_cluster_state(self.INITIAL_CLUSTER))
