What is the test required to prove a conspiracy to commit a crime?

"'Although the existence of the conspiracy must be shown by independent proof [citation], the showing need only be prima facie evidence of the conspiracy. [Citation.] The prima facie showing may be circumstantial [citation], and may be by means of any competent evidence which tends to show that a conspiracy existed. [Citation.]' (People v. Jourdain [(1980)] 111 Cal.App.3d [396,] 405.) Furthermore, the independent proof required to establish the existence of a conspiracy may consist of uncorroborated accomplice testimony. (People v. Price (1991) 1 Cal.4th 324, 444 [3 Cal.Rptr.2d 106, 821 P.2d 610]; People v. Cooks (1983) 141 Cal.App.3d 224, 312 [190 Cal.Rptr. 211].) [] . . . [] Evidence is sufficient to prove a conspiracy to commit a crime 'if it supports an inference that the parties positively or tacitly came to a mutual understanding to commit a crime. [Citation.] The existence of a conspiracy may be inferred from the conduct, relationship, interests, and activities of the alleged conspirators before and during the alleged conspiracy. [Citations.]' (People v. Cooks, supra, 141 Cal.App.3d at p. 311.)" (People v. Rodrigues (1994) 8 Cal.4th 1060, 1134-1135.)

2. Aiding and Abetting