What is the test for an act in furtherance of a defendant's right of petition or free speech?

act in furtherance of the defendant's right of petition or free speech. (City of Cotati v. Cashman (2002) 29 Cal.4th 69, 78 ["statutory phrase 'cause of action . . . arising from' means simply that the defendant's act underlying the plaintiff's cause of action must itself have been an act in furtherance of the right of petition or free speech"]; Navellier v. Sletten (2002) 29 Cal.4th 82, 89 ["the critical consideration is whether the cause of action is based on the defendant's protected free speech or petitioning activity"].) Under section 425.16, an act in furtherance of the right of petition or free speech includes "any written or oral statement or writing made in connection with an issue under consideration or review by a legislative, executive, or judicial body, or any other official proceeding authorized by law. . . ." ( 425.16, subd. (e)(2).)