Concurrency is hard. How do you test your system when it’s spread across three services and four languages? Unit testing and type systems only take us so far. At some point we need new tools.
Enter TLA+. TLA+ is a specification language that describes your system and the properties you want. This makes it a fantastic complement to testing: not only can you check your code, you can check your design, too! TLA+ is especially effective for testing concurrency problems, like stalling, race conditions, and dropped messages.
This talk will introduce the ideas behind TLA+ and how it works, with a focus on practical examples. We’ll also show how it caught complex bugs in our systems, as well as how you can start applying it to your own work.
(This is the exact same abstract as the last TLA+ talk, despite the two having just one slide in common. Writing abstracts is not my strong suite.)