What is the test for revocation of probation for a defendant on probation for failing to pay restitution?

Where a defendant on probation fails to pay restitution as ordered, the court may only revoke probation if it determines the failure to pay was willful and the defendant has the ability to pay. ( 1203.2, subd. (a).) In such cases, "the court must in some manner indicate it has considered the defendant probationer's willful failure to pay and ability to pay restitution and made a determination thereon. Although it need not recite any talismanic words or outline in detail all relevant factors it has considered in making its determination, the trial court must make apparent on the record, prior to exercising its discretion, that it has considered and weighed relevant factors in making the determinations required by the statute." (People v. Self, supra, 233 Cal.App.3d at p. 418.)