What is the test for a motion to suppress a search or seizure?

^4. "[W]hen the basis of a motion to suppress is a warrantless search or seizure, the requisite specificity is generally satisfied, in the first instance, if defendants simply assert the absence of a warrant and make a prima facie showing to support that assertion. Of course, if defendants have a specific argument other than the lack of a warrant as to why a warrantless search or seizure was unreasonable, they must specify that argument as part of their motion to suppress and give the prosecution an opportunity to offer evidence on the point. [Citation.]" (People v. Williams (1999) 20 Cal.4th 119, 130.) "[O]nce the prosecution has offered a justification for a warrantless search or seizure, defendants must present any arguments as to why that justification is inadequate. [Citation.] . . . The prosecution retains the burden of proving that the warrantless search or seizure was reasonable under the circumstances. [Citation.] But, if defendants detect a critical gap in the prosecution's proof or a flaw in its legal analysis, they must object on that basis to admission of the evidence or risk forfeiting the issue on appeal." (Ibid.)