What is the test for a motion to quash service of process on jurisdictional grounds?

" 'When a defendant moves to quash service of process on jurisdictional grounds, the plaintiff has the initial burden of demonstrating facts justifying the exercise of jurisdiction. [Citation.] Once facts showing minimum contacts with the forum state are established, however, it becomes the defendant's burden to demonstrate that the exercise of jurisdiction would be unreasonable. [Citation.] When there is conflicting evidence, the trial court's factual determinations are not disturbed on appeal if supported by substantial evidence. [Citation.] When no conflict in the evidence exists, however, the question of jurisdiction is purely one of law and the reviewing court engages in an independent review of the record. [Citation.]' " (Serafini v. Superior Court (1998) 68 Cal.App.4th 70, 77-78.)