ABAP Unit is an embedded framework to develop using the Test Driven Development approach. ABAP unit lets you test the code at unit level, independent of the entire solution.
You can always use IS BOUND to check if the Variable is instantiated or not. But, if you want to check if any variable is referring to a class or in other words, variable is declared with TYPE REF TO, you use this technique leveraging .
Exception class can be defined using to use static Text as well as the messages from the Message repository maintained using transaction SE91. In this article, lets see how to use the message from Message repository T100.