Notes for my talk Stop Writing Tests! at PyConAU. More about me on my homepage.

If you've come here for links and references mentioned in my talk, you're in the right place. I'll add more, and more detailed notes, after the event.

• Hypothesis documentation and website.
• About the ghostwriter.
• Adaptive fuzzing with HypoFuzz, related research, and an example dashboard.

Related talks:

• Sufficiently Advanced Testing, the deep-dive precursor talk I gave last year.
• watch the talk on YouTube

The most common complaint I hear about property-based testing is "I don't know what properties to test!". Fair enough! For simple properties, check out the Hypothesis ghostwriter and then read this introduction for F# - it's a classic, and has great diagrams.

In more complex cases, you'll want to reach for metamorphic properties, which are absurdly powerful (and applicable to almost everything). The coolest - and probably most complex - one I've seen is program equivalence modulo inputs (pdf), for testing compiler optimisations!

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