taken from #13128 (comment)

make video on this for https://www.youtube.com/playlist?list=PLHM9s_lN4X0hzOQ0sUmGdroxW0HfREAqj

Create page at https://github.com/checkstyle/checkstyle/tree/master/docs
to describe Test Driven Development approach in Checkstyle development and Behavior Driven Development of tests.
to show how convert issue with CLI output to test and be ready for debug of issue.