What is the test for probable cause in a search warrant?

"The pertinent rules governing a Fourth Amendment challenge to the validity of a search warrant, and the search conducted pursuant to it, are well-settled. 'The question facing a reviewing court asked to determine whether probable cause supported the issuance of the warrant is whether the magistrate had a substantial basis for concluding a fair probability existed that a search would uncover wrongdoing.' [Citations.] 'The test for probable cause is not reducible to "precise definition or quantification."' [Citation.] But we have stated that it is '"less than a preponderance of the evidence or even a prima facie case."' [Citation.] '"The task of the issuing magistrate is simply to make a practical, commonsense decision whether, given all the circumstances set forth in the affidavit before him, including the 'veracity' and 'basis of knowledge' of persons supplying hearsay information, there is a fair probability that contraband or evidence of a crime will be found in a particular place."' [Citations.] 'The magistrate's determination of probable cause is entitled to deferential review.' [Citations.] . . . [T]he warrant 'can be upset only if the affidavit fails as a matter of law to set forth sufficient competent evidence' supporting the finding of probable cause." (People v. Westerfield (2019) 6 Cal.5th 632, 659-660.)⁵