What is the test for establishing that a statement is trustworthy and falls within the declaration against interest exception?

"There is no litmus test for the determination of whether a statement is trustworthy and falls within the declaration against interest exception. The trial court must look to the totality of the circumstances in which the statement was made, whether the declarant spoke from personal knowledge, the possible motivation of the declarant, what was actually said by the declarant and anything else relevant to the inquiry. [Citations.]" (People v. Greenberger (1997) 58 Cal.App.4th 298, 334 (Greenberger).) "Clearly the least reliable circumstance is one in which the declarant has been arrested and attempts to improve his [or her] situation with the police by deflecting criminal responsibility onto others. 'Once partners in crime recognize that the 'jig is up,' they tend to lose any identity of interest and immediately become antagonists, rather than accomplices.' [Citation.] However, the most reliable circumstance is one in which the conversation occurs between friends in a noncoercive setting that fosters uninhibited disclosures. [Citations.]" (Id. at p. 335.)