Improving Model Quality by Validating Constraints with Model Unit Tests

A central part of modern development methods is the use of tests. A well-defined test suite is usually the basis for code refactoring because changes to the system under test can be easily validated against the test suite. In model-based development tests can be derived from the model but possibilities to test the originally specified model and therefore to improve the quality of model refactorings are rare. We propose a method for defining model unit tests which allows a developer to define test suites similar to the well-known xUnit testing frameworks. This gives the developer the possibility to easily check and assess model changes against valid and invalid scenarios.