Complex Systems with Patrick McKenzie (patio11)

Building software that survives contact with reality, with Will Wilson

118 snips
Sep 4, 2025
Will Wilson, CEO of Antithesis, dives into the future of software testing with a transformative approach focusing on deterministic simulation. He highlights the innovative 'time machines' his team has developed for debugging complex failures in distributed systems. From discussing the limitations of traditional testing methods to illustrating the evolution of testing with insights from classic games like Super Mario, Will emphasizes the need for robust solutions as AI begins to take the reins on coding, shaping the next era of software reliability.
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ADVICE

Fuzz The Environment With Deterministic Simulation

  • Test the environment, not just inputs: fuzz the runtime and fault conditions (network drops, crashes) to find timing-dependent bugs.
  • Use deterministic simulation testing so failures become fully repeatable and debuggable like a time machine.
ADVICE

Shorten Bug-Find Latency

  • Find bugs early to massively reduce debugging cost and latency between bug introduction and fix.
  • Keep tests and failure reproduction close to the code-change time to leverage author context and faster fixes.
ADVICE

Design For Worst-Case Counterparty Behavior

  • Assume worst-case behavior from counterparties and make your clients robust to unexpected responses.
  • Use 'bugification': deliberately inject delays or errors in test to avoid optimistic brittle assumptions.
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