The current paper presents an approach to testing of concurrent program systems based on UCM specifications usage. We have studied UCM constructions specifying multithreading system behavior. We have also described equivalent constructions using the language of basic protocols that is operated by test scenario generator. The approach to automated creation of test scenarios in MSC notation for multithreading systems has been shown. The described approach based on the analysis of concurrent threads allows us to obtain automatically verified test suites for testing concurrent distributed systems.