Abstract. Validating and transforming models are essential steps in model-driven engineering. These tasks are often implemented as opera-tions in general purpose programming languages or task-specific model management languages. Just like other software artefacts, these tasks must be tested to reduce the risk of defects. Testing model management tasks requires testers to select and manage the relevant combinations of input models, tasks and expected outputs. This is complicated by the fact that many technologies may be used in the same system, each with their own integration challenges. In addition, advanced test oracles are required: tests may need to compare entire models or directory trees. To tackle these issues, we propose creating an ...