vitest-patterns

name	vitest-patterns
description	Vitest router. Use for TypeScript/JS unit and integration tests, mocking strategy, and coverage config.

Vitest Patterns

Use when

• task changes TypeScript/JS behavior and needs unit/integration test updates
• task touches *.test.ts(x), *.spec.ts(x), vitest.config.*, or vitest.setup.*
• task introduces or modifies a vi.mock / vi.spyOn boundary

Do not use when

• task is browser end-to-end behavior (use playwright-patterns)
• task is component DOM behavior wired through Testing Library only — combine with testing-library-patterns
• task is Jest, PHPUnit, or non-Vitest framework code

Inspect first

• changed module under test and its direct imports
• nearest vitest.config.* and vitest.setup.* (environment, aliases, setup files)
• existing __mocks__ folder or shared fixtures used by neighboring tests
• coverage thresholds in vitest.config.* coverage block

Avoid mistakes

• mocking the module under test instead of its collaborators
• relying on test execution order or shared module-scope state across files
• mixing jsdom and node environments in a single suite without // @vitest-environment directive
• asserting implementation details (call counts on private helpers) instead of observable behavior

Router

1. Load references/conventions.md for naming, do/don't, and forbidden patterns.
2. Load references/scope.md for Vitest file targeting and stack boundaries.
3. Load references/workflow.md only for failing-test diagnosis and coverage flow.
4. Keep tests behavior-focused, isolated, and deterministic.

References

• references/conventions.md
• references/scope.md
• references/workflow.md