Prioritizing test scenarios from UML communication and activity diagrams

Due to the large size and complexity of software, exhaustive testing becomes impossible. Hence, testing must be done in an optimized way keeping in mind factors, such as requirements of the customer, cost and time. For this, there is a need to generate test cases and exercise them to gain maximum throughput by uncovering defects. Test case/scenario prioritization is a well known and efficient technique to ensure the software quality. Prioritization of test scenarios helps in early detection of bugs. In this paper, we present an integrated approach and a prioritization technique to generate cluster-level test scenarios from UML communication and activity diagrams. In our approach, we first construct a tree representation of communication diagrams, and then a tree representation of activity diagrams. We convert them into an intermediate tree named as COMMACT tree. We, then carry out a post-order traversal of the constructed tree for selecting conditional predicates from the intermediate tree. Then, we propose an algorithm to generate test scenarios from the constructed tree. Next, the necessary information, such as method-activity sequence, associated objects, and constraint conditions is extracted from test scenario. The test sequences are a set of theoretical paths starting from initialization to end, while taking conditions (pre- and post-condition) into consideration. Each generated test sequence corresponds to a particular scenario of the considered use case. The third phase is to generate test scenarios from the tree satisfying the message–activity path test adequacy criteria. Preliminary results obtained on a case-study indicate that the technique is effective in extracting the critical scenarios from the communication and activity diagrams. Our approach generates redundant test scenarios and still achieves adequate test coverage.