On Model-Based Regression Testing of Web-Services Using Dependency Analysis of Visual Contracts

摘要

Regression testing verifies if systems under evolution retain their existing functionality. Based on large test sets accumulated over time, this is a costly process, especially if testing is manual or the system to be tested is remote or only available for testing during a limited period. Often, changes made to a system are local, arising from fixing bugs or specific additions or changes to the functionality. Rerunning the entire test set in such cases is wasteful. Instead, we would like to be able to identify the parts of the system that were affected by the changes and select only those test cases for rerun which test functionality that could have been affected. This paper proposes a model-based approach to this problem, where service interfaces are described by visual contracts, i.e., pre and post conditions expressed as graph transformation rules. The analysis of conflicts and dependencies between these rules allows us to assess the impact of a change of the signature, contract, or implementation of an operation on other operations, and thus to decide which of the test cases is required for re-execution. Apart from discussing the conceptual foundations and justifications of the approach, we illustrate and evaluate it on a case study of a bug tracking service in several versions.