What is the test for review of an arbitration award?

"The principles governing review of an arbitration award are well established. An arbitration award is final and conclusive because the parties . . . 'have agreed that it be so.' [Citation.] Only limited judicial review is available; courts may not review the merits of the controversy, the validity of the arbitrator's reasoning, or the sufficiency of the evidence supporting the award. [Citation.] Thus, with 'narrow exceptions,' an arbitrator's decision is not reviewable for errors of fact or law. [Citation.] This is so even if the error appears on the face of the award and causes substantial injustice. [Citation.]" (Shahinian v. Cedars-Sinai Medical Center (2011) 194 Cal.App.4th 987, 999-1000.)