jest-testing-skill
Set up Jest 30+ with TypeScript for unit tests, integration tests, mocking (jest.fn, jest.mock, jest.spyOn), coverage configuration, custom matchers, snapshot testing, and setup/teardown patterns.
84
81%
Does it follow best practices?
Impact
Pending
No eval scenarios have been run
Passed
No known issues
Quality
Discovery
82%Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.
This is a strong description with excellent specificity and trigger term coverage for Jest testing with TypeScript. The main weakness is the absence of an explicit 'Use when...' clause, which would help Claude know exactly when to select this skill over others. The technical depth and version specificity make it highly distinctive.
Suggestions
Add a 'Use when...' clause such as 'Use when setting up Jest tests, configuring test coverage, writing mocks, or when the user mentions Jest, testing with TypeScript, or test configuration.'
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | Lists multiple specific concrete actions: 'unit tests, integration tests, mocking (jest.fn, jest.mock, jest.spyOn), coverage configuration, custom matchers, snapshot testing, and setup/teardown patterns' - these are all concrete, actionable capabilities. | 3 / 3 |
Completeness | Clearly answers 'what does this do' with comprehensive capabilities, but lacks an explicit 'Use when...' clause or equivalent trigger guidance explaining when Claude should select this skill. | 2 / 3 |
Trigger Term Quality | Includes excellent natural keywords users would say: 'Jest', 'TypeScript', 'unit tests', 'integration tests', 'mocking', 'jest.fn', 'jest.mock', 'jest.spyOn', 'coverage', 'snapshot testing' - covers both high-level concepts and specific API terms. | 3 / 3 |
Distinctiveness Conflict Risk | Very specific niche: Jest 30+ with TypeScript. The version specificity (30+) and technology combination (Jest + TypeScript) plus detailed feature list make it clearly distinguishable from generic testing skills or other test framework skills. | 3 / 3 |
Total | 11 / 12 Passed |
Implementation
79%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
This is a strong, actionable Jest testing skill with excellent executable examples covering the full testing spectrum from unit tests to integration tests with MSW. The main weaknesses are the lack of explicit validation/troubleshooting workflows and the monolithic structure that could benefit from splitting advanced topics into separate files.
Suggestions
Add a 'Verify Setup' section with explicit validation steps (e.g., 'Run npx jest --version to confirm installation', 'Create a minimal test to verify config works')
Add a 'Troubleshooting' section covering common failures like ESM/CJS conflicts, transform errors, and mock not working scenarios
Consider splitting MSW integration and database testing into separate reference files (e.g., MOCKING_HTTP.md, DATABASE_TESTING.md) with links from the main skill
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The skill is lean and efficient, providing executable code examples without explaining basic concepts Claude already knows. Every section earns its place with practical, copy-paste ready configurations and patterns. | 3 / 3 |
Actionability | Fully executable code throughout - complete Jest configs, test examples with proper imports, mocking patterns, and CLI commands. All examples are copy-paste ready with real TypeScript syntax. | 3 / 3 |
Workflow Clarity | While individual patterns are clear, the skill lacks explicit validation checkpoints. There's no guidance on verifying test setup works correctly, no troubleshooting steps for common failures, and no feedback loops for debugging failing tests. | 2 / 3 |
Progressive Disclosure | Content is well-organized with clear sections, but it's a monolithic document (~300 lines). The MSW mocking section and integration patterns could be split into separate reference files. References to other skills (vitest-testing-skill, github-actions-ci) are mentioned but inline content is heavy. | 2 / 3 |
Total | 10 / 12 Passed |
Validation
90%Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.
Validation — 10 / 11 Passed
Validation for skill structure
| Criteria | Description | Result |
|---|---|---|
frontmatter_unknown_keys | Unknown frontmatter key(s) found; consider removing or moving to metadata | Warning |
Total | 10 / 11 Passed | |
- Repository
- achreftlili/deep-dev-skills
- Commit
181fcbc
- Reviewed
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