GUI testing assisted by human knowledge: Random vs. functional

Software testing is a labor-intensive task in software development life-cycle. Human knowledge is useful in the practices of software testing, especially GUI testing. There are many strategies for GUI testing assisted by human knowledge, in which manual random testing and manual functional testing are two of widely used ones. In this paper, an empirical study is conducted to compare random testing and functional testing in order to provide guidelines for GUI testing. 234 participants were recruited to create thousands of random and functional test cases for open source GUI applications. Some of these test cases were selected with certain coverage criteria and then run on GUI applications to evaluate random testing and functional testing. We study three aspects on the two testing strategies: effectiveness, complementarity and impact of test case length. Some useful observations in the empirical study are: (1) Random testing is more effective in the early stage of testing on small applications and functional testing has more extensive applicability for testing large sized applications. (2) Random testing and functional testing exhibit some complementarity in our experiment. (3) Short test cases can reveal some faults more quickly and long test cases can reveal more faults lastingly.