Assessing Black-box Test Case Generation Techniques for Microservices.

Testing of microservices architectures (MSA) - today a popular software architectural style - demands for automation in its several tasks, like tests generation, prioritization and execution. Automated black-box generation of test cases for MSA currently borrows techniques and tools from the testing of RESTful Web Services. This paper: i) proposes the uTest stateless pairwise combinatorial technique (and its automation tool) for test cases generation for functional and robustness microservices testing, and ii) experimentally compares - with three open-source MSA used as subjects - four state-of-the-art black-box tools conceived for Web Services, adopting evolutionary-, dependencies- and mutation-based generation techniques, and the proposed uTest combinatorial tool. The comparison shows little differences in coverage values; uTest pairwise testing achieves better average failure rate with a considerably lower number of tests. Web Services tools do not perform for MSA as well as a tester might expect, highlighting the need for MSA-specific techniques.