Writing on slow suites and honest tests
Long-form writing from the team: how selection works, why flaky tests cost more than their minutes, and what to measure before you buy anything.
CI speed · 10 Sept 2026 · 6 min read
Hand-balanced shards drift, and nobody notices until Thursday
Splitting a suite across machines is the right first fix for a slow pipeline. Here is why the shard lists decay, and what to do before one person ends up owning them.
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Test selection · 5 Aug 2026 · 4 min read
Coverage tells you what ran, not what mattered
Line coverage and a test selection map come from the same instrumentation and answer opposite questions. Confusing them is how teams end up skipping the wrong things.
Flaky tests · 22 Jul 2026 · 5 min read
What a red build is worth once nobody believes it
A failing test is a claim about your code. A test that fails at random is a claim about nothing, and it costs more than the minutes it burns.