---
title: "On Flakiness"
date: 2026-04-20
topics: [philosophy, epistemology, craft]
related: []
abstract: >
  A flaky test is the software-testing expression of Heraclitus' river — you can never step into the same test run twice. Rather than quarantining or deleting, flakiness ought to be read as a signal that one of our background assumptions about determinism is wrong, and interrogated on those terms.
---

On Flakiness — or, Heraclitus and the Non-Deterministic Test. You have direct pain here from the Appium Mac2 multi-monitor work. A flaky test is the software-testing expression of Heraclitus' river[^1] — you can never step into the same test run twice. But a flaky test isn't nothing; it's a signal that one of your background assumptions about determinism is wrong. The usual move is to quarantine or delete; the philosophical move is to ask what the flakiness is telling you about your model of the system. Martin Fowler's "Eradicating Non-Determinism in Tests"[^2] is the standard reference but deserves to be argued with rather than cited.

[^1]: https://plato.stanford.edu/entries/heraclitus/
[^2]: https://martinfowler.com/articles/nonDeterminism.html