What is the test for making evidence of a witness unavailable as a witness?

Evidence Code section 1291, subdivision (a), provides: Evidence of former testimony is not made inadmissible by the hearsay rule if the declarant is unavailable as a witness and: [] ... [] (2) The party against whom the former testimony is offered was a party to the action or proceeding in which the testimony was given and had the right and opportunity to cross-examine the declarant with an interest and motive similar to that which he has at the hearing. A witness is considered unavailable if [a]bsent from the [51 Cal.4th 500] hearing and the proponent of his or her statement has exercised reasonable diligence but has been unable to procure his or her attendance by the court's process. ( Id., 240, subd. (a)(5).) Factors that a court should consider in determining whether reasonable diligence has been shown include the timeliness of the search, the importance of the proffered testimony, and whether leads of the witness's possible location were competently explored. ( People v. Cromer, supra, 24 Cal.4th at p. 904, 103 Cal.Rptr.2d 23, 15 P.3d 243.)

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