Unit tests have many uses. Primarily, they’re the canary in the coal mine of our code, and alert us when changes are about to go horribly wrong. When Niels’s team saw a recent change broke their unit test, they instantly knew how to fix it.

In the DONE column of the kanban board, a post it reads 'Remove Failing Test'

And look at that, it’s already moved over into the “Done” column of their Kanban board. That’s some serious productivity.