Error:does not contain a definition for '' and no extension method

The shown class ‘public class AHPModel { . . . }’ does not contain anything about AddCriteria, therefore model.AddCriteria(criteria) does not have sense. Maybe you have a separate function in another file and namespace, like ‘void AddCriteria(this AHPModel model, double [][] criteria)’? Or maybe there is another AHPModel class, which you want to test, but which is fully defined in another place.

Do you have AddCriteria or AHPModel in other places?