What is the test for making an order that a mother pay child support after a hearing in which she would have had an opportunity to argue against the order?

It follows that only the divorce court could have made an order that the mother pay an amount certain for child support after a hearing in which she would have had an opportunity to [245 Cal.App.2d 308] be heard. All that can now be said is that the father might have applied to the court for such relief; if he failed to do so and the children were in need they could, by appropriate action in the same proceeding, have brought the matter before the court. (Lewis v. Lewis, supra, 174 Cal. 336, 341, 163 P. 42.)