What is the legal test for a motion to suppress evidence obtained as a result of an improper search by police?

Under Penal Code section 1538.5, a criminal defendant may move to suppress evidence obtained as the result of an improper search by law enforcement, such as a search violating the Fourth Amendment to the United States Constitution. Our standard of review of an order denying a motion to suppress evidence " is well established. We defer to the trial court's factual findings, express or implied, where supported by substantial evidence. In determining whether, on the facts so found, the search or seizure was reasonable under the Fourth Amendment, we exercise our independent judgment. " (People v. Garry (2007) 156 Cal.App.4th 1100, 1106, 67 Cal.Rptr.3d 849, citing People v. Glaser (1995) 11 Cal.4th 354, 362, 45 Cal.Rptr.2d 425, 902 P.2d 729.)