Eslint Vitest Rule Tester
antfu-collective/eslint-vitest-rule-tester
Help users test ESLint rules with Vitest, supporting snapshot testing and custom assertions
Complete or maximize unit test coverage for a specific TypeScript file in this repo.
Install Unit Testing
$ npx skills add javierbrea/eslint-plugin-boundaries --skill unit-testing -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install javierbrea/eslint-plugin-boundaries unit-testing --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/javierbrea/eslint-plugin-boundaries.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/unit-testing .claude/skills/unit-testing && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "unit-testing" agent skill from https://github.com/javierbrea/eslint-plugin-boundaries/tree/master/.agents/skills/unit-testing into .claude/skills/unit-testing/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "unit-testing", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/javierbrea/eslint-plugin-boundaries/tree/master/.agents/skills/unit-testingType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add javierbrea/eslint-plugin-boundaries --skill unit-testing -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install javierbrea/eslint-plugin-boundaries unit-testing --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/javierbrea/eslint-plugin-boundaries.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.agents/skills/unit-testing .agents/skills/unit-testing && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "unit-testing" agent skill from https://github.com/javierbrea/eslint-plugin-boundaries/tree/master/.agents/skills/unit-testing into .agents/skills/unit-testing/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "unit-testing", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add javierbrea/eslint-plugin-boundaries --skill unit-testing -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install javierbrea/eslint-plugin-boundaries unit-testing --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/javierbrea/eslint-plugin-boundaries.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.agents/skills/unit-testing .cursor/skills/unit-testing && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "unit-testing" agent skill from https://github.com/javierbrea/eslint-plugin-boundaries/tree/master/.agents/skills/unit-testing into .cursor/skills/unit-testing/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "unit-testing", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/javierbrea/eslint-plugin-boundaries.git --path .agents/skills/unit-testing--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add javierbrea/eslint-plugin-boundaries --skill unit-testing -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install javierbrea/eslint-plugin-boundaries unit-testing --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/javierbrea/eslint-plugin-boundaries.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.agents/skills/unit-testing .gemini/skills/unit-testing && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "unit-testing" agent skill from https://github.com/javierbrea/eslint-plugin-boundaries/tree/master/.agents/skills/unit-testing into .gemini/skills/unit-testing/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "unit-testing", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install javierbrea/eslint-plugin-boundaries unit-testingInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add javierbrea/eslint-plugin-boundaries --skill unit-testing -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/javierbrea/eslint-plugin-boundaries.git skills-src && mkdir -p .github/skills && cp -r skills-src/.agents/skills/unit-testing .github/skills/unit-testing && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "unit-testing" agent skill from https://github.com/javierbrea/eslint-plugin-boundaries/tree/master/.agents/skills/unit-testing into .github/skills/unit-testing/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "unit-testing", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add javierbrea/eslint-plugin-boundaries --skill unit-testing -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install javierbrea/eslint-plugin-boundaries unit-testing --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/javierbrea/eslint-plugin-boundaries.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.agents/skills/unit-testing .opencode/skills/unit-testing && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "unit-testing" agent skill from https://github.com/javierbrea/eslint-plugin-boundaries/tree/master/.agents/skills/unit-testing into .opencode/skills/unit-testing/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "unit-testing", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
unit-testing- GitHub stars
- 997
- Token cost
- ~618 tokens
- SKILL.md length
- 236 words
- Files
- 1
- Skills in repo
- 5
- Repo updated
- First seen
- Licence
- MIT
At a glance
Complete or maximize unit test coverage for a specific TypeScript file in this repo.
- Works in 5 steps: Run the target test file with coverage… → Find missing branches by inspecting… → Add tests to hit uncovered branches.… → …
- : a test run is short of the 100% coverage threshold and you need to find and close the gap
- SKILL.md covers Completing coverage for a… and Handling unreachable or…
- Calls pnpm
What it does
Unit Testing is an agent skill from javierbrea/eslint-plugin-boundaries. Complete or maximize unit test coverage for a specific TypeScript file in this repo. Use when: a test run is short of the 100% coverage threshold and you need to find and close the gap, or when deciding whether an uncovered branch is genuinely unreachable. For everyday test-writing conventions (AAA, mocking, placement, type safety), see .agents/rules/unit-testing.md instead — it loads automatically for any .spec.ts file.
Its SKILL.md is about 620 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Testing & QA, covering Unit testing. It works with TypeScript and ESLint. The repository describes itself as: Enforce architectural boundaries in your JavaScript and TypeScript projects. The licence is MIT.
When your agent uses it
- : a test run is short of the 100% coverage threshold and you need to find and close the gap
- Deciding whether an uncovered branch is genuinely unreachable
Example prompts
- “/unit-testing”
Workflow steps
5 steps, taken from the first numbered list in SKILL.md.
- Run the target test file with coverage to get a baseline
- Find missing branches by inspecting packages//coverage/lcov.info for BRDA entries with zero hits. Map uncovered branches to exact…
- Add tests to hit uncovered branches. Re-run after each change. Repeat until resolved or justified.
- Prefer adding tests over suppressing coverage.
- If uncovered logic appears obsolete, do not change production code — present evidence and request user confirmation first.
What it can do on your machine
Read from SKILL.md and the folder at commit 50f2d31. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
pnpm
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md. Its commands use pnpm, which can reach the network depending on how they are called.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Unit Testing loads about 618 tokens when it runs. Until then it costs about 110 tokens; SKILL.md has 236 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from javierbrea/eslint-plugin-boundaries at commit 50f2d31, republished under its MIT licence (© javierbrea). 236 words, ~618 tokens.
Download SKILL.mdSave it as
.claude/skills/unit-testing/SKILL.md (or your agent's skills folder).- name
- unit-testing
- description
- Complete or maximize unit test coverage for a specific TypeScript file in this repo. Use when: a test run is short of the 100% coverage threshold and you need to find and close the gap, or when deciding whether an uncovered branch is genuinely unreachable. For everyday test-writing conventions (AAA, mocking, placement, type safety), see .agents/rules/unit-testing.md instead — it loads automatically for any *.spec.ts file.
- argument-hint
- Path to target test or source file under packages/ (e.g., packages/elements/src/Matcher/ElementsMatcher.ts)
Unit Testing — closing coverage gaps
All packages enforce 100% coverage (branches, functions, lines, statements) via jest.config.js's coverageThreshold.global; any drop below fails the build. For AAA structure, mocking, placement, and type safety, follow .agents/rules/unit-testing.md — this skill only covers the coverage-completion workflow. For the general Nx-vs-direct command choice, see the root AGENTS.md.
Completing coverage for a specific file
- Run the target test file with coverage to get a baseline:
bash cd packages/<package-name> pnpm test:unit <test-file> - Find missing branches by inspecting
packages/<package-name>/coverage/lcov.infoforBRDAentries with zero hits. Map uncovered branches to exact conditions in the source. - Add tests to hit uncovered branches. Re-run after each change. Repeat until resolved or justified.
- Prefer adding tests over suppressing coverage.
- If uncovered logic appears obsolete, do not change production code — present evidence and request user confirmation first.
Handling unreachable or defensive branches
When a branch is genuinely unreachable at runtime and cannot be exercised through tests, mark it with an istanbul ignore comment that justifies why:
/* istanbul ignore next -- Defensive guard: invalid parser state is impossible through public API */Rules for istanbul ignore:
- Always include a justification after the
--separator. - Prefer making code non-optional over ignoring it. If a default is never exercised, remove it instead of adding an ignore comment.
- Only use for genuinely unreachable code. If a branch can be triggered through a public API, write a test for it.
- Keep the ignore scope as narrow as possible. Place on the specific line or branch, not on entire functions.
© javierbrea, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
Just SKILL.md in .agents/skills/unit-testing of javierbrea/eslint-plugin-boundaries.
Open the folder on GitHubat commit 50f2d31
Compare with similar skills
Unit Testing next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Unit Testing this skilljavierbrea/eslint-plugin-boundaries | 997 | — | ~618 | Automated safety check: Pass | MIT | |
| Eslint Vitest Rule Testerantfu-collective/eslint-vitest-rule-tester | 142 | — | ~1.3k | Automated safety check: Pass | MIT | |
| Run Pre Commit Checksmicrosoft/vscode-python-environments | 141 | — | ~898 | Automated safety check: Pass | MIT | |
| Typescriptalinaqi/maggy | 707 | — | ~1.3k | Automated safety check: Pass | MIT | |
| Typescript Rulessoftspark/ai-toolkit | 179 | — | ~2.7k | Automated safety check: Notes | Apache-2.0 | |
| Implementing Lint Rulesflint-fyi/flint | 311 | — | ~857 | Automated safety check: Pass | MIT |
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- Official
Run Pre Commit Checks
microsoft/vscode-python-environments
Run the mandatory pre-commit checks before committing code. An agent skill from microsoft/vscode-python-environments.
Typescript
alinaqi/maggy
TypeScript strict mode with eslint and jest. An agent skill from alinaqi/maggy.
Typescript Rules
softspark/ai-toolkit
TypeScript/JavaScript coding rules: style, patterns, security, testing.
Implementing Lint Rules
flint-fyi/flint
Implements ESLint-style lint rules with proper AST handling, targeted reporting, and comprehensive unit tests.
Npx CLI
jwynia/agent-skills
Build and publish npx-executable CLI tools using Bun as the primary toolchain with npm-compatible output.
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Create or update a GitHub pull request for the current branch from the repository's fixed PR template (.github/PULLREQUESTTEMPLATE.md) and the branch changes.
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Related
Works with
Categories
Questions about Unit Testing
What does Unit Testing do?
Complete or maximize unit test coverage for a specific TypeScript file in this repo. Unit Testing is an agent skill from javierbrea/eslint-plugin-boundaries. Complete or maximize unit test coverage for a specific TypeScript file in this repo.
When should I use Unit Testing?
Unit Testing fits situations like: : a test run is short of the 100% coverage threshold and you need to find and close the gap; deciding whether an uncovered branch is genuinely unreachable.
How do I install Unit Testing in Claude Code?
Run `npx skills add javierbrea/eslint-plugin-boundaries --skill unit-testing -a claude-code`. Or copy the skill folder (.agents/skills/unit-testing in javierbrea/eslint-plugin-boundaries) into .claude/skills/unit-testing in your project. Claude Code loads it when a task matches its description.
How do I install Unit Testing in Codex?
Run `npx skills add javierbrea/eslint-plugin-boundaries --skill unit-testing -a codex`. Or copy the skill folder (.agents/skills/unit-testing in javierbrea/eslint-plugin-boundaries) into .agents/skills/unit-testing in your project. Codex loads it when a task matches its description.
Can I use Unit Testing in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add javierbrea/eslint-plugin-boundaries --skill unit-testing -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/unit-testing, .gemini/skills/unit-testing, .github/skills/unit-testing and .opencode/skills/unit-testing in your project.
What does Unit Testing need to run?
Going by SKILL.md and its folder, Unit Testing needs the command-line tools its instructions call (pnpm).
Does Unit Testing access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Unit Testing safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Unit Testing use?
Unit Testing is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Unit Testing use?
About 618 tokens (SKILL.md is roughly 2.5k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Unit Testing?
Skills that share tags, products or a category with Unit Testing: Eslint Vitest Rule Tester (antfu-collective/eslint-vitest-rule-tester, 142 stars), Run Pre Commit Checks (microsoft/vscode-python-environments, 141 stars), Typescript (alinaqi/maggy, 707 stars) and Typescript Rules (softspark/ai-toolkit, 179 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Unit Testing?
javierbrea (a GitHub user) maintains it in javierbrea/eslint-plugin-boundaries, which has 997 GitHub stars. The repository holds 5 skills in this directory. The repository was last updated on October 5, 2026.
Source: javierbrea/eslint-plugin-boundaries on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.