test-driven-development
Implements a feature or bug fix test-first: write one failing test, run it and watch it fail, write the minimal code to pass, then refactor with the tests green. Use when a change alters code behavior: a new feature, a bug fix, or a behavior change, whether the request comes alone or through delivery-flow.
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The canonical home for this skill is test-driven-development in tesslio/tessl-eval-demo
Test-Driven Development
Write the test first. Watch it fail. Write the minimal code to pass. Refactor with the tests green.
Rules
- No production code without a failing test first. Code written before its test is deleted and written again from the test.
- A bug fix starts with a test that reproduces the bug.
- If the test is hard to write, the design is unclear: simplify the interface.
- When writing or changing a test, read references/writing-good-tests.md.
Before you say it is done
- Each new behavior has a test that you saw fail first.
- The full suite passes on the final code.
- Repository
tesslio/tessl-eval-demo
- Revision
5cb6fa3
- Last updated
- First committed
Canonical home
since Oct 13, 2026
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