During the development process, sequence diagrams are used for the following primary purposes:
Therefore, there is a need to facilitate comparison between sequence diagrams because, in principle at least, they must be identical. The execution message sequence must match the specification message sequence. You could also use this tool to compare two runs for regression testing.
If all execution sequence diagrams are identical to their corresponding specification (nonanimated) sequence diagrams, the system satisfies the requirements as captured in the use cases. However, if there are differences, you need to determine whether the specification was inaccurate or an error exists in the implementation. In both cases, correct the modeling error (either in the statechart or the sequence diagram) and then repeat the testing cycle to determine whether you have fixed the problem.