cuioss/jest-testing

JavaScript Testing Standards

Unit testing standards for JavaScript projects using Jest, covering test structure, DOM interaction, web component testing, mocking, async patterns, and coverage.

Enforcement

• Prohibited actions: Do not generate tests that depend on implementation internals; do not use arbitrary setTimeout waits in tests
• Constraints: Tests must follow AAA (Arrange-Act-Assert) pattern; each test verifies one behavior

Prerequisites

• Jest 29+
• jsdom test environment (for DOM/component testing)
• @testing-library/jest-dom (recommended for DOM assertions)

Workflow

Step 1: Load Test Fundamentals

Load this standard for any JavaScript test work.

Read: standards/test-fundamentals.md

Covers framework setup, test structure, naming, AAA pattern, parameterized tests, coverage configuration, and ESLint integration for tests.

Step 2: Load Additional Standards (As Needed)

DOM and Component Testing (load for UI/component tests):

Read: standards/dom-component-testing.md

Use when: Testing DOM manipulation, web components (Lit/custom elements), Testing Library queries, container-based component testing, or accessibility assertions.

Mocking and Async Patterns (load for mocking or async code):

Read: standards/mocking-async.md

Use when: Mocking modules or APIs, working with fetch mocks, testing async/await code, controlling timers, or managing test isolation.

Related Skills

• plan-marshall:persona-module-tester — Language-agnostic testing methodology (AAA, coverage, reliability)
• pm-dev-frontend:javascript — Core JavaScript development standards
• pm-dev-frontend:lint-config — ESLint configuration including Jest plugin