What is the test for a judicial review of an award made by an arbitrator at an arbitration?

encompasses the arbitrator's resolution of questions of law or fact. Because the finality of arbitration awards is rooted in the parties' agreement to bypass the judicial system, ordinarily '"[t]he merits of the controversy between the parties are not subject to judicial review." [Citations.]' [Citation.]" (Cooper v. Lavely & Singer Professional Corp., supra, 230 Cal.App.4th at pp. 11-12.) Because the issue of whether the arbitrator exceeded his powers is a legal question based on undisputed facts, our review on that point is de novo. (Richey v. AutoNation, Inc. (2015) 60 Cal.4th 909, 918, fn.1 (Richey).)