Mutation-Based Integration Testing of Knowledge Graph Applications

With the advent of AI-driven applications, testing faces new challenges when it comes to the integration of software with AI components. We present a novel testing approach to tackle the integration of software with symbolic AI in the form of knowledge graphs (KG). As the KG is expected to change during the run- and lifetime of the software, we must ensure the robustness of the system w.r.t. changes in the KG. Starting with a singular KG, we mutate its content and test the unchanged software with the original test oracle. To address the specific challenges of KGs, we introduce two additional concepts. First, as generic mutations on single triples are too fine-grained to reliably generate a KG describing a different, consistent KG, we employ domain-specific mutation operators, that manipulate subgraphs in a domain-adherent way. Second, we need to specify those parts of the knowledge that the software relies on for correctness. We introduce the notion of a robustness mask as shapes in the graph that the mutant must conform to. We evaluate our approach on two software applications from the robotic and simulation domain that tightly integrate with their respective KG.