Test Coverage of Data-Centric Dynamic Compositions in Service-Based Systems

This paper addresses the problem of integration testing of data-centric dynamic compositions in service-based systems. These compositions define abstract services, which are replaced by invocations to concrete candidate services at runtime. Testing all possible runtime instances of a composition is often unfeasible. We regard data dependencies between services as potential points of failure, and introduce the k-node data flow test coverage metric. Limiting the level of desired coverage helps to significantly reduce the search space of service combinations. We formulate the problem of generating a minimum set of test cases as a combinatorial optimization problem. Based on the formalization we present a mapping of the problem to the data model of FoCuS, a coverage analysis tool developed at IBM. FoCuS can efficiently compute near-optimal solutions, which we then use to automatically generate and execute test instances of the composition. We evaluate our prototype implementation using an illustrative scenario to show the end-to-end practicability of the approach.