Generate Tests Often and Keep 100% Coverage

As stated in the modelling section, frequent test generation is the key to succeeding in completion of modelling. Rarely lack of coverage “fixes itself” but requires conscious actions. Lack of coverage is not a problem – actually it allows you to learn more about the functionality you are modelling, e.g., the interplay of data with control flow which in turn will allow you to find inconsistencies in the specification or your thinking about the application to be testing. The following sections give more detail on how to work with coverage.

Once a model starts to become complex (see Model Complexity) and test generation time exceeds your threshold of patience, start to generate tests from subactivity diagrams, i.e., by setting a sub activity diagram to be the “main diagram” and generating tests. This technique should be used to study in particular newly added functionality in isolation before you evaluate it as part of the full model. Note that you may need to prepare the activity diagrams before using them in isolation (e.g., copy and initialize [state] variables temporarily into the isolated diagrams).