javascript-testing-patterns
Implement comprehensive testing strategies using Jest, Vitest, and Testing Library for unit tests, integration tests, and end-to-end testing with mocking, fixtures, and test-driven development. Use when writing JavaScript/TypeScript tests, setting up test infrastructure, or implementing TDD/BDD workflows.
63
75%
Does it follow best practices?
Impact
—
No eval scenarios have been run
Passed
No known issues
Optimize this skill with Tessl
npx tessl skill review --optimize ./plugins/javascript-typescript/skills/javascript-testing-patterns/SKILL.mdQuality
Discovery
100%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 skill description that clearly articulates specific capabilities (testing frameworks, test types, techniques), includes abundant natural trigger terms that developers would use, and explicitly states both what the skill does and when to use it. The description is concise yet comprehensive, covering the domain thoroughly without unnecessary verbosity.
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | Lists multiple specific concrete actions and tools: 'Jest, Vitest, and Testing Library for unit tests, integration tests, and end-to-end testing with mocking, fixtures, and test-driven development.' This covers specific frameworks, test types, and techniques. | 3 / 3 |
Completeness | Clearly answers both 'what' (implement testing strategies using specific tools for specific test types) and 'when' (explicit 'Use when writing JavaScript/TypeScript tests, setting up test infrastructure, or implementing TDD/BDD workflows'). | 3 / 3 |
Trigger Term Quality | Includes strong natural keywords users would say: 'Jest', 'Vitest', 'Testing Library', 'unit tests', 'integration tests', 'end-to-end testing', 'mocking', 'fixtures', 'TDD', 'BDD', 'JavaScript/TypeScript tests', 'test infrastructure'. These cover a wide range of terms a developer would naturally use. | 3 / 3 |
Distinctiveness Conflict Risk | Clearly scoped to JavaScript/TypeScript testing with specific frameworks (Jest, Vitest, Testing Library) and methodologies (TDD/BDD). This is a well-defined niche that is unlikely to conflict with other skills like general coding, deployment, or non-JS testing skills. | 3 / 3 |
Total | 12 / 12 Passed |
Implementation
50%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
The skill provides highly actionable, executable code examples across multiple testing patterns, which is its primary strength. However, it is excessively verbose, spending hundreds of lines on patterns Claude already knows well (basic unit testing, CRUD testing, simple mocking). The content reads more like a tutorial for junior developers than a skill file for Claude, and the best practices section is entirely generic knowledge that wastes tokens.
Suggestions
Cut the trivial examples (calculator tests, basic CRUD class tests) and focus only on non-obvious patterns like module mocking, DI testing, and fixture factories that add genuine value beyond Claude's existing knowledge.
Remove the 'When to Use This Skill' section and the 15-item best practices list—Claude already knows these fundamentals and they consume significant tokens.
Add a clear TDD workflow with sequenced steps (e.g., 1. Write failing test → 2. Run and verify failure → 3. Implement minimal code → 4. Run and verify pass → 5. Refactor) since TDD is mentioned in the description but not actually taught.
Provide the referenced 'references/advanced-testing-patterns.md' bundle file, or inline the most critical advanced patterns and remove the dangling references.
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | Extremely verbose at ~400+ lines. Includes trivial examples Claude already knows (testing add/divide functions, basic CRUD class tests). The 'When to Use This Skill' section is unnecessary padding. The best practices list of 15 items is generic knowledge Claude already possesses. Many patterns could be condensed significantly. | 1 / 3 |
Actionability | All code examples are fully executable TypeScript with complete imports, proper test structure, and realistic patterns. Configuration files for Jest and Vitest are copy-paste ready. Mocking patterns show concrete, working implementations including module mocks, DI mocks, and spies. | 3 / 3 |
Workflow Clarity | The skill presents individual testing patterns clearly but lacks a coherent workflow for setting up testing from scratch or implementing TDD. There's no sequenced process with validation checkpoints—it's more of a reference catalog. The best practices list is a flat enumeration without actionable workflow guidance. | 2 / 3 |
Progressive Disclosure | References to 'references/advanced-testing-patterns.md' are well-signaled and one level deep, which is good. However, no bundle files were provided, so the referenced file doesn't exist. The main file itself is monolithic with too much inline content that could be split out (e.g., mocking patterns, framework configs), while the sections that were split out (integration testing, frontend testing) are reduced to vague summaries. | 2 / 3 |
Total | 8 / 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 |
|---|---|---|
skill_md_line_count | SKILL.md is long (538 lines); consider splitting into references/ and linking | Warning |
Total | 10 / 11 Passed | |
- Repository
- wshobson/agents
- Commit
34632bc
- Reviewed
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