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aitchnyu • yesterday at 10:47 AM • 1 reply • view on HN

Now that code is cheap, I ensured my side project has unit/integration tests (will enforce 100% coverage), Playwright tests, static typing (its in Python), scripts for all tasks. Will learn mutation testing too (yes, its overkill). Now my agent works upto 1 hour in loops and emits concise code I dont have to edit much.

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EastLondonCoder • yesterday at 4:06 PM

Totally get it, and I think we’re describing the same control loop from different angles.

Where I differ slightly is: “100% coverage” can turn into productivity theatre. It’s a metric that’s easy to optimize while missing the thing you actually care about: do we have machine-checkable invariants at the points where drift is expensive?

The harness that’s paid off for me (on a live payments system) is:

  - thin vertical slice first (end-to-end runnable, even if ugly)

  - tests at the seams (payments, emails, ticket verification / idempotency)

  - state-machine semantics where concurrency/ordering matters

  - unit tests as supporting beams, not wallpaper
Then refactors become routine, because the tests will make breakage explicit.

So yes: “code is cheap” -> increase verification. Just careful not to replace engineering judgement with an easily gamed proxy.