Efficient Test Generation Guided by Field Coverage Criteria.

Field-exhaustive testing is a testing criterion suitable for object-oriented code over complex, heap-allocated, data structures. It requires test suites to contain enough test inputs to cover all feasible values for the object's fields within a certain scope (input-size bound). While previous work shows that field-exhaustive suites can be automatically generated, the generation technique required a formal specification of the inputs that can be subject to SAT-based analysis. Moreover, the restriction of producing all feasible values for inputs' fields makes test generation costly. In this paper, we deal with field coverage as testing criteria that measure the quality of a test suite in terms of coverage and mutation score, by examining to what extent the values of inputs' fields are covered. In particular, we consider field coverage in combination with test generation based on symbolic execution to produce underapproximations of field-exhaustive suites, using the Symbolic Pathfinder tool. To underapproximate these suites we use tranScoping, a technique that estimates characteristics of yet to be run analyses for large scopes, based on data obtained from analyses performed in small scopes. This provides us with a suitable condition to prematurely stop the symbolic execution. As we show, tranScoping different metrics regarding field coverage allows us to produce significantly smaller suites using a fraction of the generation time. All this while retaining the effectiveness of field exhaustive suites in terms of test suite quality.