Guided Test Case Generation through AI Enabled Output Space Exploration

Black-box software testing is a crucial part of quality assurance for industrial products. To verify the reliable behavior of software intensive systems, testing needs to ensure that the system produces the correct outputs from a variety of inputs. Even more critical, it needs to ensure that unexpected corner cases are tested. Existing approaches attempt to address this problem by the generation of input data to known outputs based on the domain knowledge of an expert. Such input space exploration, however, does not guarantee an adequate coverage of the output space as the test input data generation is done independently of the system output. The paper discusses a novel test case generation approach enabled by neural networks which promises higher probability of exposing system faults by systematically exploring the output space of the system under test. As such, the approach potentially improves the defect detection capability by identifying gaps in the test suite of uncovered system outputs. These gaps are closed by automatically determining inputs that lead to specic outputs by performing backward reasoning on an artificial neural network. The approach is demonstrated on an industrial train control system.