What is the test for splitting a cause of action?

"The rule against splitting a cause of action is based upon two reasons: (1) That the defendant should be protected against vexatious litigation; and (2) that it is against public policy to permit litigants to consume the time of the courts by relitigating matters already judicially determined, or by asserting claims which properly should have been settled in some prior action." (Wulfjen v. Dolton, 24 Cal.2d 891, 894-895, 151 P.2d 840.)