ABAP Unit does not replace good system or integration testing, but it can prepare your code so that these tests can be successfully completed in a shorter time period.
ABAP Unit Test class, a simpler way to verify the behavior of our code. The unit test class not only check the code coverage but helps a developer to cover all possible scenarios of a code leading to more reliable code with less chances of rework.
SAP Business Workflow was built on an approximation of object orientated programming called the Business Object Repository or BOR. It uses object oriented techniques which allowed developers the ability to create copies of standard BOR objects, modify them and through inheritance allow them to be used in place of the standard.