Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add byerlikaya/claude-starter-kit --skill testinggit clone --depth 1 https://github.com/byerlikaya/claude-starter-kitWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/byerlikaya/claude-starter-kit/testing)<a href="https://agentmods.dev/skills/byerlikaya/claude-starter-kit/testing"><img src="https://agentmods.dev/badge/skills/byerlikaya/claude-starter-kit/testing.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00061 | $0.00779 |
| Opus 5 | $0.00030 | $0.00390 |
| Sonnet 5 | $0.00012 | $0.00156 |
| Haiku 4.5 | $0.00006 | $0.00078 |
Grade A, and why
testing scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 52 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Testing Discipline
Trigger phrases: "write a test", "run the tests", "coverage", "are the tests green", "unit test", "integration test", "tests pass locally", "flaky test", "test is flaky"
Goal: behavior correctness — test real behavior without breaking product code just to make a test pass.
Principles
- Pyramid: many unit, fewer integration, few end-to-end (e2e). Limit e2e to critical flows.
- AAA: Arrange-Act-Assert; one test = one behavior.
- Isolation & determinism: external dependencies are mocked/faked; time and randomness are fixed; test order is independent.
- Risk-coverage: risk, not metrics. Critical path + boundary + negative + authorization (IDOR/404) scenarios.
- Naming:
what_it_tests_under_which_condition_what_it_expects— on failure it is clear what broke. - Red-green: first a failing test, then the implementation.
Watch out
- Flaky = bug: an occasionally failing test is not tolerated; it is fixed at the root.
- In snapshot/golden-file tests, avoid needless brittleness (assert only the meaningful output).
Tests that cannot fail
Green is evidence only if the test could have gone red. Shapes that check nothing:
- Assertion restates the code: it recomputes the implementation's own expression, so it moves with every change.
- Setup guarantees the result: arrange plants the value the assert reads back; it holds even if the act never ran.
- Expected value derived the way the code derives it: same formula, query or parser — the same wrong assumption on both sides still matches.
- A double asserted against its own stub: the fake is told to return X and the test asserts X; only the fake runs.
- No assertion: it passes because nothing threw. If not throwing is the behavior under test, assert that.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 6d ago First seen · 52 lines · 61 tokens per session scan A 8550a04a0536
testing is a skill published in the GitHub repository byerlikaya/claude-starter-kit (22 stars, last pushed 6d ago), licensed MIT. It adds 61 tokens to every session and 779 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other skills, from other repositories
verify-implementation
A workflow that runs a project’s verification skills to produce a report on coding patterns, architecture rules, and project conventions. It is intended for work after implementation, before a pull request, or during code review.
verification-engine
Use when verifying build/test/lint before commit, PR, or completion claims. Runs verification pipeline in fresh subagent context with auto-repair. Triggers on /handoff-verify, pre-commit check, build verification, test validation.
accessibility-a11y
WCAG 2.2 compliance, ARIA patterns, keyboard navigation, screen readers, automated testing.
eval-harness
Formal evaluation framework for Claude Code sessions implementing eval-driven development (EDD) principles.
dependency-upgrade
Manage major dependency version upgrades with compatibility analysis, staged rollout, and comprehensive testing. Use when upgrading framework versions, updating major dependencies, or managing breaking changes in libraries.
migrate-to-shoehorn
Migrate test files from as type assertions to @total-typescript/shoehorn. Use when user mentions shoehorn, wants to replace as in tests, or needs partial test data.