Testing Software and Systems: 30th IFIP WG 6.1 International Conference, ICTSS 2018, Cádiz, Spain, October 1-3, 2018, Proceedings

Writing a regular expression that exactly captures a set of desired strings is difficult, since regular expressions provide a compact syntax that makes it difficult to easily understand their meaning. Testing is widely used to validate regular expressions. Indeed, although a developer could have problems in writing the correct regular expression, (s)he can easily assess whether a string should be accepted or not. Starting from this observation, we propose an iterative mutation-based process that is able to test and repair a faulty regular expression. The approach consists in generating strings S that distinguish a regular expression r from its mutants, asking the user to assess the correct evaluation of S, and possibly substituting r with a mutant r ′ that evaluates S more correctly than r ; we propose four variants of the approach which differ in the policy they employ to judge whether r ′ is better than r . Experiments show that the proposed approach is able to actually repair faulty regular expressions with a reasonable user’s effort.