Test Driven Development

This skill enforces strict TDD discipline: write a failing test, watch it fail, write minimal code to pass, then refactor. It's uncompromising about order. If you wrote code before the test, you delete it and start over, no exceptions. The guidance is direct about common rationalizations like "I'll test after" or "keep it as reference" and systematically refutes them. Use this when you want to follow red-green-refactor religiously, not when you want flexibility about testing approaches. The tone is deliberately forceful because TDD's value comes from the discipline, not loose adherence. If you're the type who skips tests "just this once," this will push back hard.

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last updated: Jul 14, 2026

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Install

$ npx -y skills add sickn33/antigravity-awesome-skills --skill test-driven-development --agent claude-code

Installs into .claude/skills of the current project.

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Test-Driven Development (TDD)

Overview

Write the test first. Watch it fail. Write minimal code to pass.

Core principle: If you didn't watch the test fail, you don't know if it tests the right thing.

Violating the letter of the rules is violating the spirit of the rules.

When to Use

Use for behavior changes where a repeatable test can demonstrate the requirement or reproduce the bug. Inspect the repository’s test runner and existing coverage first. For copy, generated outputs or low-impact configuration, use the appropriate focused validation rather than manufacturing a unit test.

Preserve existing work

Write the failing regression before the repair when feasible, and verify that it fails for the expected reason. If implementation already exists, preserve it and add characterization/regression tests. Do not delete user work, reset a branch or rewrite working code to reconstruct an ideal test-first history. State honestly whether the test preceded the fix.