What is the test for premeditation in a murder case?

"[W]e must determine in any [127 Cal.App.3d 1020] case of circumstantial evidence whether the proof is such as will furnish a reasonable foundation for an inference of premeditation and deliberation [citations], or whether it 'leaves only to conjecture and surmise the conclusion that defendant either arrived at or carried out the intention to kill as the result of a concurrence of deliberation and premeditation.' ..." (People v. Anderson (1968) 70 Cal.2d 15, 25, 73 Cal.Rptr. 550, 447 P.2d 942, emphasis original.)