What is the test for determining whether a pretrial identification procedure violates a defendant's due process rights?

A pretrial identification procedure violates a defendant's due process rights if it is so impermissibly suggestive that it creates a very substantial likelihood of irreparable misidentification. The defendant bears the burden of proving unfairness as a "demonstrable reality," not just speculation. (Simmons v. United States (1968) 390 U.S. 377, 384, 88 S.Ct. 967, 971, 19 L.Ed.2d 1247; People v. Sanders (1990) 51 Cal.3d 471, 508, 273 Cal.Rptr. 537, 797 P.2d 561; People v. Perkins (1986) 184 Cal.App.3d 583, 589, 229 Cal.Rptr. 219.)

On review we must consider the totality of the circumstances to determine whether the identification procedure was unconstitutionally suggestive. We must resolve all evidentiary conflicts in favor of the trial court's findings and uphold them if supported by substantial evidence. (People v. Wimberly (1992) 5 Cal.App.4th 773, 788, 7 Cal.Rptr.2d 152.)