ABAP Unit tests are executed by executing test tasks in the context of test runs. Test tasks can comprise one or more ABAP programs to be tested; these programs contain test classes which in turn contain test methods. During a test run, the test methods of the relevant test tasks are called by a test driver in the runtime environment; duplicate tests are only executed once.
The order in which the tests are executed is not specified deterministically. Since the tests are independent unit tests, the test sequence is irrelevant. It is certain that:
All methods of a test class are executed together.
All test classes of a program are executed together.