[{"_1":2,"_3":-5,"_4":-5},"loaderData",{"_5":6,"_7":8},"actionData","errors","root",{"_28":-5,"_38":-5,"_39":40,"_41":42,"_43":44,"_45":46,"_47":48,"_49":50,"_51":52,"_53":54},"routes/_store+/_readers+/email_author.$slug/route",{"_9":10,"_11":-5},"book",{"_12":13,"_14":15,"_16":17,"_18":19,"_20":21,"_22":23},"currentUser","id","Z2lkOi8vbGVhbnB1Yi9TdG9yZTo6Qm9va1Byb2R1Y3QvMzQ4NTI","title","Property-Based Testing in a Screencast Editor","state","published","contactAuthorMethod","email","aboutText","

This is a short book on using property-based testing (PBT) within Komposition, a screencast editor.

First, this book introduces the system under test (SUT), Komposition. Next, it goes into PBT and highlights some challenges in testing properties of an application like Komposition. Finally, the main part of the book is compromised of case studies. Each case study covers increasingly complex components and how they are tested. It includes this author's personal reflections, what bugs the tests have found, and what still remains to be improved.

This is not a tutorial on PBT, but rather a collection of motivating examples. That said, you should be able to follow along without prior knowledge of PBT.

For example, it explains how using PBT helped find and fix bugs in the specification and implementation of Komposition's video classifier. Those were bugs that would be very hard to find using example-based tests or using a static type system.

This book is based on articles published on https://wickstrom.tech. While the content is mostly the same, there are few changes bringing it up-to-date. Also, if you've already enjoyed the articles, you might want support my work by purchasing this book. Finally, you might enjoy a nicely typeset PDF, or an EPUB book, over a web page.

To post a review, go to Goodreads.com: https://www.goodreads.com/book/show/47969546-property-based-testing-in-a-screencast-editor

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Kick off your book project in 3 hours! Live workshop on Zoom. You’ll leave with a real book project, progress on your first chapter, and a clear plan to keep going. Saturday, May 2, 2026. Learn more…

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