What is the test for a mistake of fact defense?

that the sheathed knife accidently came to be in his back pocket. Mainard testified, "I don't know how it could be in my rear pocket on my belt. My belt only goes this far." Thus, there was no substantial evidence to support a mistake of fact instruction and Mainard did not rely upon mistake of fact as a defense during trial. Consequently, the trial court properly denied a mistake of fact instruction. (People v. Brooks, supra, 3 Cal.5th at p. 73.)

Lastly, any error in failing to instruct on the mistake of fact defense is subject to review under the People v. Watson (1956) 46 Cal.2d 818, 836, harmless error standard. (People v. Hanna (2013) 218 Cal.App.4th 455, 462.) Under this standard, reversal of a conviction is warranted only if it is reasonably probable the defendant would have obtained a more favorable outcome had the instruction been given. (People v. Watson, supra, 46 Cal.2d at p. 836.)