Mistral has gained tremendous traction recently. Both OpenStack components and third parties are writing and executing tons of workflows every day. Unfortunately, testing these workflows is usually a trial and error process which is especially problematic when the workflows take a long time to execute, are hard to repeat, or are interacting with external systems. Not to mention covering the error cases. Mistral workflows can be tested just as any other code. In this technical/hands-on presentation we will show how you can "unit test" workflows, what debugging tools are available and how you can integrate these tests in CI pipelines.