Watch mode

--watch reruns tests when Python source files change:

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uv run karva test --watch

What triggers a re-run

Karva watches Python source files under the project root. Edits to .py files queue a fresh run; edits to other files are ignored.

The watcher debounces rapid saves so a single editor write does not produce multiple runs.

Combining with other flags

Combine --watch with test selection:

Re-run only the tests that failed last time, then everything once they pass:

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uv run karva test --watch --last-failed

Watch one test:

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uv run karva test --watch -E 'test(/^pkg::test_login$/)'

To exit, press Ctrl-C.