What is the test for a motion for a mistrial?

"A trial court should grant a motion for mistrial 'only when "'a party's chances of receiving a fair trial have been irreparably damaged'"' [citation], that is, if it is 'apprised of prejudice that it judges incurable by admonition or instruction' [citation]. 'Whether a particular incident is incurably prejudicial is by its nature a speculative matter, and the trial court is vested with considerable discretion in ruling on mistrial motions.' [Citation.] Accordingly, we review a trial court's ruling on a motion for mistrial for abuse of discretion. [Citation.]" (People v. Avila (2006) 38 Cal.4th 491, 573.)