What is the test for making a specific offer of proof in a motion to overturn an evidentiary ruling?

"Given this record, the rule requiring a specific offer of proof in order to preserve an evidentiary ruling for appeal comes into play. (Evid. Code, 354.) An offer of proof should give the trial court an opportunity to change or clarify its ruling and in the event of appeal would provide the reviewing court with the means of determining error and assessing prejudice. [Citation.] To accomplish these purposes an offer of proof must be specific. It must set forth the actual evidence to be produced and not merely the facts or issues to be addressed and argued. [Citations.]" (People v. Schmies (1996) 44 Cal.App.4th 38, 53.)