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.

Quality

70%

Does it follow best practices?

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Securityby

Passed

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tessl review fix ./testing/jest-testing-skill/SKILL.md

Quality

Content

65%Weight 40%Scale 1-5

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

The content is highly actionable and largely concise, packed with executable patterns, but it functions as a monolithic reference rather than a sequenced, validated workflow and does not use progressive disclosure to split detail into reference files.

Suggestions

Fix the Jest config key 'setupFilesAfterSetup' to 'setupFilesAfterEach' so the setup file actually loads.

Add a short sequenced setup workflow with a validation checkpoint, e.g. '3. Run `npx jest` on a sample spec to confirm the toolchain works before expanding.'

Move the larger blocks (MSW handlers/server, docker-compose.test.yml, full SWC config) into reference files under references/ and link to them from SKILL.md to apply progressive disclosure.

Dimension	Reasoning	Score
Conciseness	The body is mostly lean code with minimal prose and assumes Claude's competence, but it is long (~450 lines) with some redundancy — e.g. the ts-jest and SWC config blocks overlap substantially — that could be trimmed.	4 / 5
Actionability	It provides copy-paste-ready, executable examples across the common cases (config, mocking, spies, factories, matchers, snapshots, timers, MSW), but the config uses a non-standard key 'setupFilesAfterSetup' (correct Jest option is 'setupFilesAfterEach'), a minor gap that keeps it below fully executable.	4 / 5
Workflow Clarity	A rough scaffold sequence exists (install, config:init, optional SWC) but there is no explicit numbered setup workflow and no validation checkpoint (e.g. 'run a sample test to confirm the setup'), so checkpoints are missing or implicit.	3 / 5
Progressive Disclosure	The body has good section headers but no bundle files exist, so all content — including sizable blocks like MSW setup and the test-database compose file that could live in references — is inlined in a single 450-line SKILL.md with no one-level-deep references.	3 / 5
	Total	14 / 20 Passed

Description

75%Weight 40%Scale 1-5

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

The description is specific, comprehensive, and clearly distinct, but it lacks any 'when to use' trigger guidance, which caps its completeness. Adding a 'Use when ...' clause would raise the score materially.

Suggestions

Add an explicit trigger clause, e.g. 'Use when setting up or refactoring Jest tests in a TypeScript project, or when the user mentions Jest, unit/integration tests, mocking, snapshots, or coverage.'

Include natural synonyms and file extensions (e.g. 'test doubles, spies, stubs, .spec.ts, .test.ts') to broaden trigger-term coverage toward anchor 5.

Keep the third-person voice but ensure the description stands alone as a complete what+when statement rather than only a capability list.

Dimension	Reasoning	Score
Specificity	The description enumerates multiple concrete capabilities — 'unit tests, integration tests, mocking (jest.fn, jest.mock, jest.spyOn), coverage configuration, custom matchers, snapshot testing, and setup/teardown patterns' — giving comprehensive coverage of what the skill sets up.	5 / 5
Completeness	There is a clear 'what' (set up Jest 30+ with TypeScript for a detailed capability list) but no 'Use when...' clause or equivalent explicit trigger guidance, so per the judging guideline completeness is capped at 3.	3 / 5
Trigger Term Quality	Strong natural keywords users would say ('Jest', 'TypeScript', 'unit tests', 'integration tests', 'mocking', 'snapshot testing', 'coverage') plus specific API names, but it omits synonyms ('test doubles', 'spies/stubs') and file extensions (.spec.ts, .test.ts) that anchor 5 expects.	4 / 5
Distinctiveness Conflict Risk	'Set up Jest 30+ with TypeScript' carves a clear niche with distinct triggers and minimal conflict risk; the explicit framework name and version distinguish it from related testing skills.	5 / 5
	Total	17 / 20 Passed

Validation

93%

Warnings & errors only

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation — 15 / 16 Passed

Validation for skill structure

Criteria	Description	Result
frontmatter_unknown_keys	Unknown frontmatter key(s) found; consider removing or moving to metadata	Warning

	Total	15 / 16 Passed

Repository: achreftlili/deep-dev-skills
Path: testing/jest-testing-skill/SKILL.md
Commit: 181fcbc

Reviewed: 1 day ago

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