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Want to understand why some of your @vitest.dev tests are slower than expected? Then you can use the built-in experimental @opentelemetry.io support to figure out what makes tests slow and how much time is spent on each part of it. 📈

VoidZero

@voidzero.dev

When enabled, Vitest will generate traces automatically, while you are also able to add custom tracing to it. More on GitHub github.com/vitest-dev/v... PS: Keep in mind that OTEL will increase the time of the tests when enabled.

github.comStabilizing `openTelemetry` · vitest-dev vitest · Discussion #9222experimental.openTelemetry Introduced in 4.0.11 Docs: Config option Guide Rational: It could be hard to analyze the performance of your tests with built-in tools like a CPU Profiler (for example, N...

17/12/25, 5:24 pm0 reposts5 likes

Pipo

@pipo-dev.bsky.social

23 Apr

Could you tell me what kind of data I can get from this out of the box? I tried it with the given configs, but it seems like I more or less "just" see the duration of the individual test files? Can I deep dive somehow why/where tests took long? Or do I have to write custom instrumentation for this?