A motor insurer

Where the simple bank is for reading, this model is for running. Its four use cases create the model’s three entities (clients, policies and claims), which an execution environment keeps, checking every pre- and post-condition against them as it runs. Process claim is the one to read closely: it waits for the client’s documents against a deadline, screens and prices the claim, and then declines it or has it assessed, paid and the vehicle repaired.

Who answers each lower-level service is configuration, not model: the same model runs with people, stubs, compiled services or external systems behind them. It keeps one defect on purpose, to show what an integrated test run catches that unit runs cannot.