After my first implementation of BREP boolean algorithm I started running into the corner cases like coincident vertices/edges/surfaces and etc. 

It was a time to create a testing framework  for BREP sub-system to track the regressions and to test the quality of the boolean algorithm on the crazy data.

Here is the view of my testing framework. I have creates 73 automated  tests for brep boolean so far:

Here are some examples of the corner case. All these objects are created by applying the boolean operations on a box.