How do I install the Testing skill?

Run npx skillmds@latest add bumgeunsong/testing in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Testing safe to use?

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Which AI agents work with Testing?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Testing free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Testing?

bumgeunsong (@bumgeunsong) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Testing by bumgeunsong — Agent Skill

Name: Testing
Author: bumgeunsong

Testing

Use when writing, adding, or modifying tests (*.test.ts, *.test.tsx, *.integration.test.tsx), adding coverage, implementing business logic, or doing TDD — unit tests for pure functions AND integration tests for components/hooks (React Query cache, MSW-mocked Supabase, React Router data-router loaders). Routes to strategy, naming, unit, integration, spec, and mutation-verification references. Does NOT cover cross-page journeys (use Playwright E2E in apps/web/tests/).

bumgeunsong 6158d6f 7 files · 48.6 KB Updated Sep 17, 2026

File contents

Writing Tests

The single source of truth for test rules is references/. This skill routes there. Read the docs in order and write to their rules.

The goal is not coverage. The goal is trust: after reading this test, can you trust the implementation more?

Read order

references/strategy.md — Define the risk you are blocking in one sentence, then place the code in the deep×wide quadrant to pick the level: unit / integration / don't-test / refactor-first.
references/spec.md — For high-stakes features (payment, issuance, PII, feature-flag gates, or code with fix-commit history), confirm a domain answer-sheet (정답지) first. Ask the user once; skip for obvious pure-logic utils.
Level doc — Write with the rules of the level strategy picked:
- references/unit.md — pure functions, output-based, boundary+exception.
- references/integration.md — components/hooks/loaders, MSW + React Query + data-router, user-observable results.
references/verification.md — If you added or changed an assertion, run the mutation loop to filter false-green. Skip for pure refactors (but record the skip).

Test names follow references/naming.md at every level.

File conventions

Tests are colocated with source (next to the file, or in a sibling __tests__/). Two Vitest projects, routed by filename:

Kind	Extension	Vitest project	Setup	MSW
Unit	`*.test.ts(x)`	`unit`	`setupTest.ts`	off
Integration	`*.integration.test.tsx`	`integration`	`setupTest.ts` + `setupTest.integration.ts`	on (`onUnhandledRequest: 'error'`)

Missing the .integration suffix routes the file to the unit project with no MSW → silent false green. This is the #1 filename mistake.

Config: apps/web/vite.config.ts (test.projects). Run: pnpm --filter web test / test:run / test:coverage.
E2E (Playwright, apps/web/tests/*.spec.ts, local Supabase) is out of scope for this skill.

Stack facts (assume these; verify if surprised)

React Query v4, React Router v6 data-router (createBrowserRouter, loaders, lazy).
Backend calls go to Supabase REST (/rest/v1/*, /auth/v1/*); tests mock the network with MSW, never the Supabase SDK.
Render helper: renderWithProviders (src/test/utils/renderWithProviders.tsx). Auth: signInAs (src/test/utils/signInAs.ts) or vi.mock('@/shared/hooks/useAuth') — see integration.md.
No Stryker; mutation verification is manual, using vitest run <file> --coverage (v8) for reachability.

---name: testingdescription: Use when writing, adding, or modifying tests (*.test.ts, *.test.tsx, *.integration.test.tsx), adding coverage, implementing business logic, or doing TDD — unit tests for pure functions AND integration tests for components/hooks (React Query cache, MSW-mocked Supabase, React Router data-router loaders). Routes to strategy, naming, unit, integration, spec, and mutation-verification references. Does NOT cover cross-page journeys (use Playwright E2E in apps/web/tests/).---# Writing TestsThe single source of truth for test rules is `references/`. This skill routes there. Read the docs in order and write to their rules.The goal is not coverage. **The goal is trust: after reading this test, can you trust the implementation more?**## Read order1. **[references/strategy.md](references/strategy.md)** — Define the risk you are blocking in one sentence, then place the code in the deep×wide quadrant to pick the level: unit / integration / don't-test / refactor-first.2. **[references/spec.md](references/spec.md)** — For high-stakes features (payment, issuance, PII, feature-flag gates, or code with fix-commit history), confirm a domain answer-sheet (정답지) first. Ask the user once; skip for obvious pure-logic utils.3. **Level doc** — Write with the rules of the level strategy picked: - **[references/unit.md](references/unit.md)** — pure functions, output-based, boundary+exception. - **[references/integration.md](references/integration.md)** — components/hooks/loaders, MSW + React Query + data-router, user-observable results.4. **[references/verification.md](references/verification.md)** — If you added or changed an assertion, run the mutation loop to filter false-green. Skip for pure refactors (but record the skip).Test names follow **[references/naming.md](references/naming.md)** at every level.## File conventionsTests are colocated with source (next to the file, or in a sibling `__tests__/`). Two Vitest projects, routed by filename:| Kind | Extension | Vitest project | Setup | MSW ||---|---|---|---|---|| Unit | `*.test.ts(x)` | `unit` | `setupTest.ts` | off || Integration | `*.integration.test.tsx` | `integration` | `setupTest.ts` + `setupTest.integration.ts` | on (`onUnhandledRequest: 'error'`) |**Missing the `.integration` suffix routes the file to the unit project with no MSW → silent false green.** This is the #1 filename mistake.- Config: `apps/web/vite.config.ts` (`test.projects`). Run: `pnpm --filter web test` / `test:run` / `test:coverage`.- E2E (Playwright, `apps/web/tests/*.spec.ts`, local Supabase) is out of scope for this skill.## Stack facts (assume these; verify if surprised)- React Query **v4**, React Router **v6** data-router (`createBrowserRouter`, loaders, lazy).- Backend calls go to **Supabase REST** (`/rest/v1/*`, `/auth/v1/*`); tests mock the **network with MSW**, never the Supabase SDK.- Render helper: `renderWithProviders` (`src/test/utils/renderWithProviders.tsx`). Auth: `signInAs` (`src/test/utils/signInAs.ts`) or `vi.mock('@/shared/hooks/useAuth')` — see integration.md.- No Stryker; mutation verification is manual, using `vitest run <file> --coverage` (v8) for reachability.

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