What is the test for obtaining an anonymous tip from a police community support officer?

In Florida v. J.L., the police received one anonymous telephone call reporting that a suspect matching defendant's description, and at his location at a bus stop, had a gun. The court found that anonymous tip, under those particular circumstances, not to be sufficiently reliable so as to be the sole basis for a detention and pat-search. The court noted, however, that "there are situations in which an anonymous tip, suitably corroborated, exhibits 'sufficient indicia of reliability to provide reasonable suspicion to make the investigatory stop.' " (Florida v. J.L., supra, 120 S.Ct. 1375, 1378.) The tip in that case was found lacking as it "provided no predictive information and therefore left the police without means to test the informant's knowledge or credibility." (Ibid.) Even the inclusion in the tip of a physical description of the suspect was found lacking for this purpose, as "[t]he reasonable suspicion here at issue requires that a tip be reliable in its assertion of illegality, not just in its tendency to identify a determinate person." (Ibid.)