Do you write unit tests to confirm bugfixes? (aka Red-Green-Refactor)

When you encounter a bug in your application you should never let the same bug happen again. The best way to do this is to write a unit test for the bug, see the test fail, then fix the bug and watch the test pass. This is also known as Red-Green-Refactor.

Tip: you can then reply to the bug report with "Done + Added a unit test so it can't happen again"