What is the test for abuse of discretion in the context of a discretionary decision?

"We review a trial court's evidentiary rulings for abuse of discretion. [Citation.] . . . Discretion is abused only when in its exercise, the trial court 'exceeds the bounds of reason, all of the circumstances before it being considered.' [Citation.] . . . A trial court will abuse its discretion by action that is arbitrary or ' "that transgresses the confines of the applicable principles of law." ' [Citations.] In appeals challenging discretionary trial court rulings, it is the appellant's burden to establish an abuse of discretion. [Citations.]" (Shaw v. County of Santa Cruz (2008) 170 Cal.App.4th 229, 281.)