What is the test for a motion to suppress evidence under section 1538.5 of the California Criminal Code?

"A defendant may move to suppress evidence under section 1538.5 on grounds that a search without a warrant was unreasonable. A warrantless search is presumptively unreasonable, and the prosecution bears the burden of demonstrating a legal justification for the search. [Citation.] In reviewing a trial court's ruling on a motion to suppress, we defer to the trial court's factual findings, express or implied, where supported by substantial evidence. [Citation.] And in determining whether, on the facts so found, the search was reasonable for purposes of the Fourth Amendment to the United States Constitution, we exercise our independent judgment." (People v. Simon (2016) 1 Cal.5th 98, 120 (Simon).)