What is the test for a plaintiff to assert a statute of limitations defense?

9 Estoppel to assert a statute of limitations defense requires that the plaintiff allege in his complaint " 'acts or conduct affirmatively engaged in [by the defendant] to procure delay for purposes of settlement, or investigation or otherwise, upon which the [plaintiff] has relied and by which he has been induced to delay the filing of a claim until after the expiration of the statutory period.' " (Muraoka v. Budget Rent-A-Car, Inc. (1984) 160 Cal.App.3d 107, 116, 206 Cal.Rptr. 476.)