What is the test for attacking the validity of a search?

As has often been pointed out, whether or not to attack the validity of a search, whether by raising issues of reasonable grounds for a non-warrant arrest or by way of a traverse of the affidavit underlying a warrant, is a matter of trial tactics, of great delicacy and on which the decision of counsel must prevail on appeal. The attack will inevitably bring out the very kind of bad character that a defense usually bends every effort to keep out of the record and only counsel can determine whether the chances of success outweigh the certainty of prejudice. Except in an extreme case, supported by extreme facts of record, an appellate court may not second guess the trial counsel. (People v. Garrison (1966) 246 Cal.App.2d 343, 350, 356, 54 Cal.Rptr. 731.)