What is the test for exhaustion of remedies in a collective bargaining agreement?

As explained in Cone v. Union Oil Co., supra 129 Cal.App.2d at page 564, 277 P.2d at page 468, '(t)his rule, which is analogous to the rule requiring the exhaustion of administrative remedies as a condition precedent to resorting to the courts (citation), is based on a practical approach to the myriad problems, complaints and grievances that arise under a collective bargaining agreement. It makes possible the settlement of such matters by a simple, expeditious and inexpensive procedure, and by persons who, generally, are intimately familiar therewith. (Citation.) The use of these internal remedies for the [70 Cal.App.3d 680] adjustment of grievances is designed not only to promote settlement thereof but also to foster more harmonious employee-employer relations. (Citation.) Such procedures, which have been worked out and adopted by the parties themselves, must be pursued to their conclusion before judicial action may be instituted unless circumstances exist which would excuse the failure to follow through with the contract remedies.'