Automating Test Case Identification in Open Source Projects on GitHub

Software testing is one of the very important Quality Assurance (QA) components. A lot of researchers deal with the testing process in terms of tester motivation and how tests should or should not be written. However, it is not known from the recommendations how the tests are actually written in real projects. In this paper the following was investigated: (i) the denotation of the test word in different natural languages; (ii) whether the test word correlates with the presence of test cases; and (iii) what testing frameworks are mostly used. The analysis was performed on 38 GitHub open source repositories thoroughly selected from the set of 4.3M GitHub projects. We analyzed 20,340 test cases in 803 classes manually and 170k classes using an automated approach. The results show that: (i) there exists weak correlation (r = 0.655) between the word test and test cases presence in a class; (ii) the proposed algorithm using static file analysis correctly detected 95\% of test cases; (iii) 15\% of the analyzed classes used main() function whose represent regular Java programs that test the production code without using any third-party framework. The identification of such tests is very low due to implementation diversity. The results may be leveraged to more quickly identify and locate test cases in a repository, to understand practices in customized testing solutions and to mine tests to improve program comprehension in the future.