What is the test for dismissing a complaint-in-intervention?

"...Substantively, as well as procedurally, employer and employee actions are interchangeable: regardless of who brings an action, it is essentially the same lawsuit." (County of San Diego v. Sanfax Corp., supra, 19 Cal.3d at pp. 872, 874, 140 Cal.Rptr. 638, 568 P.2d 363, emphasis added.)

In dismissing the complaint-in-intervention the trial court relied upon Johnson v. Santos (1983) 148 Cal.App.3d 566, 196 Cal.Rptr. 145, a case [210 Cal.App.3d 752] decided by this court. In Santos an employee sued a third party for work-related injuries; the compensation carrier later intervened. Subsequently, the employee elected arbitration and received an award of damages. The five years for prosecution lapsed before the defendant sought a trial de novo. The defendant then successfully obtained dismissal of the complaint and complaint-in-intervention under the mandatory five-year statute contained at that time in section 583, subdivision (b). The intervener/compensation carrier appealed. (Johnson v. Santos, supra, 148 Cal.App.3d at pp. 568-569, 196 Cal.Rptr. 145.)