What is the test for a defendant's right to remain silent?

People v. Rundle(2008) 43 Cal.4th 76, 115, 74 Cal.Rptr.3d 454, 180 P.3d 224, disapproved on other grounds in People v. Doolin(2009) 45 Cal.4th 390, 421, fn. 22, 87 Cal.Rptr.3d 209, 198 P.3d 11; see

[194 Cal.Rptr.3d 813]

also People v. Thomas(2012) 211 Cal.App.4th 987, 1006, 150 Cal.Rptr.3d 361[viewed in the context of a number of expressions of frustration, the defendant's single statement, I ain't talking no more and we can leave it at that, could be viewed as another expression of momentary frustration and, at most, was an ambiguous invocation of the right to remain silent].)