Seeding strategies in search-based unit test generation

Search-based techniques have been applied successfully to the task of generating unit tests for object-oriented software. However, as for any meta-heuristic search, the efficiency heavily depends on many factors; seeding, which refers to the use of previous related knowledge to help solve the testing problem at hand, is one such factor that may strongly influence this efficiency. This paper investigates different seeding strategies for unit test generation, in particular seeding of numerical and string constants derived statically and dynamically, seeding of type information and seeding of previously generated tests. To understand the effects of these seeding strategies, the results of a large empirical analysis carried out on a large collection of open-source projects from the SF110 corpus and the Apache Commons repository are reported. These experiments show with strong statistical confidence that, even for a testing tool already able to achieve high coverage, the use of appropriate seeding strategies can further improve performance. (C) 2016 The Authors. Software Testing, Verification and Reliability published by John Wiley & Sons, Ltd.