This paper is devoted to model-driven testing technique of testing model generation from UML sequence diagram to UML Testing profile. The article discusses principles of model transformation and shows practical approach to specific model generation from another one. The idea of such transformation is to generate test cases from sequence diagram of the system. Described transformation rules are focused on timing aspect verification and the goal of generated test cases is to cover successful as well as unsuccessful system behaviour. Presented example of model transformation is based on a sequence diagram XMI representation, which firstly is pre-processed and moved into data base structures, and then transformation rules applied to generate testing model from data describing sequence diagram.