What is the test for suppressing evidence in a criminal case?

In a proceeding under Penal Code section 1538.5 to suppress evidence, ". . . the power to judge the credibility of the witnesses, resolve any conflicts in the testimony, weigh the evidence and draw factual inferences, is vested in the trial court. On appeal all presumptions favor the exercise of that power, and the trial court's findings on such matters, whether express or implied, must be upheld if they are supported by substantial evidence." (People v. Lawler (1973) 9 Cal.3d 156, 160.)