What is the definition of a 'criminal street gang' and what is the test for membership of a criminal street gang?

association with any criminal street gang.' [Citation.] A criminal street gang, in turn, is defined by the Act as any 'ongoing organization, association, or group of three or more persons' that shares a common name or common identifying symbol; that has as one of its 'primary activities' the commission of certain enumerated offenses; and 'whose members individually or collectively' have committed or attempted to commit certain predicate offenses. [Citation.] To prove that a criminal street gang exists in accordance with these statutory provisions, the prosecution must demonstrate that the gang satisfies the separate elements of the STEP Act's definition and that the defendant sought to benefit that particular gang when committing the underlying felony." (People v. Prunty (2015) 62 Cal.4th 59, 66-67, fn. and italics omitted.)

"The STEP Act defines a 'criminal street gang' as an 'ongoing organization, association, or group.' [Citation.] That 'group' must have 'three or more persons,' and its 'primary activities' must consist of certain crimes. [Citation.] The same 'group' must also have 'a common name or common identifying sign or symbol,' and its members must be proven to have engaged in a 'pattern of criminal gang activity' by committing predicate offenses." (People v. Prunty, supra, 62 Cal.4th at p. 71.)