Test Driven Development
Use when implementing non-trivial code changes that should follow TDD (write a failing test first, make the smallest passing change, then refactor safely).
Install
$ agentstack add skill-narumiruna-skills-test-driven-development ✓ scanned · ✓ verified, works with Claude Code, Cursor, and more.
Security review
✓ PassedNo issues found. Passed automated security review. · v0.1.0 How review works →
- ✓ Prompt-injection patterns
- ✓ Secret / credential exfiltration
- ✓ Dangerous shell & filesystem operations
- ✓ Untrusted network calls
- ✓ Known-malicious package signatures
What it can access
- ✓ Network access No
- ✓ Filesystem access No
- ✓ Shell / process execution No
- ✓ Environment & secrets No
- ✓ Dynamic code execution No
From automated source analysis of v0.1.0. “Used” means the capability is present in the source — more access means more to trust, not that it’s unsafe.
Verified badge
Passed review? Show it. Paste this badge into your README, it links to the public security report.
Links to your public security report.[](https://agentstack.voostack.com/security/report/skill-narumiruna-skills-test-driven-development) Reliability & compatibility
Declared compatibility
Compatibility is declared by the source manifest. End-to-end runtime verification is coming, see below.
We're building live execution health for every listing: tool-call success rate, median latency, uptime, and last-checked timestamps, measured, not self-reported. It isn't live yet, so we don't show numbers we can't stand behind.
How agent discovery & health will work →About
TDD Policy
- Non-trivial changes SHOULD begin with a test.
- A test SHOULD fail before implementation begins whenever practical (red → green → refactor).
- Implementation SHOULD follow the red → green → refactor cycle.
- Implement the smallest change required to make the test pass.
- Refactoring MUST happen only after tests pass and MUST NOT change behavior.
- Tests MUST act as executable specifications of behavior, not merely coverage.
- Tests MUST assert observable behavior, not implementation details.
- Bug fixes SHOULD include a regression test when feasible.
- Code changes SHOULD include corresponding test updates when behavior changes.
- Tests MUST be deterministic and isolated from uncontrolled inputs (for example network, time, or randomness).
- Tests SHOULD avoid reliance on external systems unless explicitly intended.
- External dependencies SHOULD be controlled appropriately.
- Tests SHOULD target the lowest meaningful level.
- Integration and end-to-end tests SHOULD complement lower-level tests where needed.
- Tests MUST NOT be weakened or removed to satisfy incorrect implementations.
- Tests SHOULD fail for a single clear reason.
- When tests cannot be added, this MUST be rare and explicitly justified, including:
- why testing is not feasible
- what risk remains
- how the change was validated
- Skipping TDD for non-trivial changes REQUIRES explicit justification.
Scope
- Non-trivial changes include:
- Bug fixes
- New features
- Behavior changes
- Data transformations
- Business logic or query changes
- Excluded:
- Pure formatting changes
- Renames without behavior change
- Comment or documentation updates
Exceptions
- TDD MAY be relaxed for:
- Rapid prototyping or spike solutions
- Exploratory coding where requirements are unclear
- Pure UI layout or styling changes
Source & license
This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.
- Author: narumiruna
- Source: narumiruna/skills
- License: MIT
Install and usage instructions live in the source repository linked above.
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Versions
- v0.1.0 Imported from the upstream source.