DUnit is an Xtreme testing framework for Borland Delphi programs.
It was originally inspired on the JUnit framework written in Java by Kent Beck and Erich Gamma, but has evolved into a tool that uses much more of the potential of Delphi to be much more useful to Delphi developers.
DUnit automates unit testing of Delphi code. The target audience for DUnit is developers who are both writing the code to be tested and the unit tests for that code, an approach advocated by Extreme Programming. Dunit is is a Delphi port of JUnit.
Reference:
http://dunit.sourceforge.net/README.html
DUnit is a framework of classes designed to support the Xtreme approach to software testing.
The idea is that, as you develop or change code, you develop appropriate verification tests at the same time, rather than postponing them to a later test phase.
By keeping the tests up-to-date and re-applying them at regular intervals, it becomes easier to produce reliable code, and to be confident that alterations (and refactorings) do not break existing code.
Applications become self-testing.
DUnit supplies classes that make it easy to organize and run these tests.
Jump to writting DUnit test cases
http://dunit.sourceforge.net/README.html#_Getting_started