Longer is Better: On the Role of Test Sequence Length in Software Testing

In the presence of an internal state, often it is required a sequence of function calls to test software. In fact, to cover a particular branch of the code, a sequence of previous function calls might be required to put the internal state in the appropriate configuration. Internal states are not only present in object-oriented software, but also in procedural software(e.g., static variables in C programs). In the literature, there are many techniques to test this type of software. However, to our best knowledge, the properties related to choosing the length of these sequences have received only little attention in the literature. In this paper, we analyse the role that the length plays in software testing, in particular branch coverage. We show that on “difficult” software testing benchmarks longer test sequences make their testing trivial. Hence, we argue that the choice of the length of the test sequences is very important in software testing.