AI agent skills for writing tests
Test-writing skills are mostly about restraint: what to assert, what to mock, and when a test is testing the framework rather than your code. A good one pins the project's test runner and conventions so the agent stops inventing a new style per file, and insists on a failing test before the fix. Watch for skills that chase a coverage number — coverage is a symptom, and a skill that optimizes it directly will write tests that execute lines without checking anything.
People land here searching for “claude code skill for writing tests”, “agent skill unit tests”, “tdd skill for cursor”.
767 writing tests skills Refine in search →
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gongyijie85 Skill Rust TestingRust testing patterns including unit tests, integration tests, async testing, property-based testing, mocking, and coverage. Follows TDD methodology. Use when writing Rust tests — unit, integration, async, property-based, or coverage.
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junmystery Skill Rust TestingRust testing patterns including unit tests, integration tests, async testing, property-based testing, mocking, and coverage. Follows TDD methodology. Use when writing Rust tests — unit, integration, async, property-based, or coverage.
- junmystery Skill Rust Testing 2
Rust testing patterns including unit tests, integration tests, async testing, property-based testing, mocking, and coverage. Follows TDD methodology. Use when writing Rust tests — unit, integration, async, property-based, or coverage.
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dmitriyyukhanov Skill Unity Tests WriteUse when writing Unity tests, including EditMode tests, PlayMode tests, performance testing, and code coverage
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pluginagentmarketplace Bundle Go TestingGo testing practices - unit tests, benchmarks, mocks, coverage
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affaan-m Skill Rust TestingWrite reliable, maintainable Rust tests using unit tests, integration tests, async testing, property-based testing, mocking, and coverage following TDD methodology.
Audited 226k -
itsnex1s Skill TestingTesting with Vitest, Jest, and Playwright. Use for unit tests, integration tests, E2E tests, and coverage reports.
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majiayu000 Bundle Unity TestingThis skill should be used when the user asks about "tests", "unit tests", "EditMode tests", "PlayMode tests", "Test Runner", "test coverage", "NUnit", "Assert", "test fixtures", "writing tests", "running tests", or discusses Unity testing patterns and practices.
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janszewczyk Bundle Unit TestingWrite unit tests with Vitest for TypeScript projects — mocking, async testing, parameterized tests, server action testing, and coverage. Use when writing unit tests for utilities, server-side logic, schemas, or pure functions.
- majiayu000 Bundle Test Quality 2
Guides strong, effective unit test generation using proven testing techniques. Use when writing unit tests, reviewing test quality, improving existing tests, generating test cases, checking test coverage strength, or when tests exist but may be weak. Triggers on: unit test, test quality, test coverage, write tests, improve tests, review tests, test strength, mutation testing, boundary testing.
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gannonh Bundle Writing IOS Unit TestsUse this skill when writing iOS unit tests, debugging test failures, creating Swift Testing tests, testing SwiftData models, or when the user asks to add tests, fix tests, improve coverage, or test Swift code. Covers Swift Testing framework, ModelContainer lifecycle, and coverage requirements.
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mhassan0000 Skill Rust TestingGuides writing Rust tests with TDD, covering unit, integration, async, property-based, mocking, and coverage patterns.
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oimiragieo Bundle Comprehensive Unit Testing With PytestAims for high test coverage using pytest, testing both common and edge cases.
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tomevault-io Bundle Test 19Run unit tests with coverage Use when this capability is needed.
- tomevault-io Bundle Mariotaddeucci Agent Skill Router Pytest Coverage
Pytest Coverage Skill
- tomevault-io Bundle Test Coverage 4
Test coverage analysis and strategies for comprehensive testing. Use this when improving test coverage or analyzing what tests are missing. Use when this capability is needed.
- tomevault-io Bundle Unit Testing 6
Unit testing standards following TDD methodology, test pyramid principles, and comprehensive coverage practices. Covers pytest, Jest, mocking, fixtures, and CI integration for reliable test suites. Use when this capability is needed.
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javierbrea Skill Unit TestingComplete 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.
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az9713 Skill TestingTesting patterns, strategies, and best practices for comprehensive test coverage.
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livelybug Skill Rust TestingRust testing patterns including unit tests, integration tests, async testing, property-based testing, mocking, and coverage. Follows TDD methodology.
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diegosouzapw Bundle Comprehensive Unit Testing With PytestAims for high test coverage using pytest, testing both common and edge cases.
54 - majiayu000 Bundle Test Coverage
Analyze test coverage and suggest tests for uncovered code
567 - majiayu000 Bundle Unit Test Oprogramadorreal Optimus Claude
Improves unit test coverage on demand — discovers testing gaps and generates tests that follow project conventions. Requires /optimus:init to have set up test infrastructure first. Conservative — only adds new test files, never refactors existing source code. Supports `deep` mode for iterative in-conversation test generation and `deep harness` mode for an automated multi-cycle unit-test + testability-refactor loop with fresh context per phase. Use when test coverage is low, after adding new code that lacks tests, or when you want an automated coverage-improvement harness.
567 - majiayu000 Bundle Fullstack Testing
Fullstack testing - unit, integration, E2E, coverage
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How to install a writing tests skill
- Compare the skills. Read the writing tests skills below — each page shows the full SKILL.md, its safety verdict, and the capabilities it declares.
- Install it. Run npx skillmds@latest add <owner>/<name>. The CLI writes the skill into every agent directory it detects, or use --agent to pin one.
- Use it. Restart your agent. It loads the skill on demand the next time you ask for something that matches — you do not have to name the skill.
What makes a good writing tests skill?
Test-writing skills are mostly about restraint: what to assert, what to mock, and when a test is testing the framework rather than your code. A good one pins the project's test runner and conventions so the agent stops inventing a new style per file, and insists on a failing test before the fix. Watch for skills that chase a coverage number — coverage is a symptom, and a skill that optimizes it directly will write tests that execute lines without checking anything.
Every skill listed here is a plain SKILL.md file in the format Anthropic documents for Agent Skills, read unchanged by Cursor, OpenAI Codex and 60+ agents. Each passes a safety review before it is publicly listed; the verdict and declared capabilities are on every skill's page.
Frequently asked questions
What is an agent skill for writing tests?
Test-writing skills are mostly about restraint: what to assert, what to mock, and when a test is testing the framework rather than your code. A good one pins the project's test runner and conventions so the agent stops inventing a new style per file, and insists on a failing test before the fix. Watch for skills that chase a coverage number — coverage is a symptom, and a skill that optimizes it directly will write tests that execute lines without checking anything.
Will a test skill work with my test runner?
Most are runner-agnostic and read your existing tests to infer conventions. Where a skill is specific — Jest, pytest, Go's testing package, RSpec — it says so in its description, and the skill page's frontmatter shows exactly what it expects.
Which agents can use these writing tests skills?
Any agent that reads SKILL.md files: Claude Code, Claude.ai, Cursor, OpenAI Codex, Windsurf, OpenCode and 60+ others. The format is not vendor-specific, so the same file works everywhere — each agent just keeps its skills in a different directory, listed at /agents.
Are these writing tests skills free?
Yes. Searching, reading and installing skills on SkillMD is free and needs no account. Individual skills carry their own licence, shown on each skill's page.