vitest

name	vitest
description	Vitest (Vite-powered) testing — Jest-compatible API, vi mocks, coverage, environments, projects/workspaces. Use when writing or fixing tests, vitest.config.ts, coverage, or monorepo test commands in AFENDA-HYBRID (@afenda/db, @afenda/ui-core, view-engine, erp-view-pack). Prefer https://vitest.dev for Vitest 4.x when reference snippets disagree.
metadata	{"author":"Anthony Fu","version":"2026.1.28","source":"Generated from https://github.com/vitest-dev/vitest, scripts located at https://github.com/antfu/skills","official_docs":"https://vitest.dev"}

Vitest is a next-generation testing framework powered by Vite. It provides a Jest-compatible API with native ESM, TypeScript, and JSX support out of the box. Vitest shares the same config, transformers, resolvers, and plugins with your Vite app.

Key Features:

• Vite-native: Uses Vite's transformation pipeline for fast HMR-like test updates
• Jest-compatible: Drop-in replacement for most Jest test suites
• Smart watch mode: Only reruns affected tests based on module graph
• Native ESM, TypeScript, JSX support without configuration
• Multi-threaded workers for parallel test execution
• Built-in coverage via V8 or Istanbul
• Snapshot testing, mocking, and spy utilities

Reference material was generated from Vitest docs (see GENERATION.md); wording may reflect an older minor series.

Version alignment (this repo): pnpm-workspace.yaml catalogs Vitest ^4.1.0. For new options, breaking changes, or browser mode, confirm against the official Vitest guide and config reference.

Core

Topic	Description	Reference
Configuration	Vitest and Vite config integration, defineConfig usage	core-config
CLI	Command line interface, commands and options	core-cli
Test API	test/it function, modifiers like skip, only, concurrent	core-test-api
Describe API	describe/suite for grouping tests and nested suites	core-describe
Expect API	Assertions with toBe, toEqual, matchers and asymmetric matchers	core-expect
Hooks	beforeEach, afterEach, beforeAll, afterAll, aroundEach	core-hooks

Features

Topic	Description	Reference
Mocking	Mock functions, modules, timers, dates with vi utilities	features-mocking
Snapshots	Snapshot testing with toMatchSnapshot and inline snapshots	features-snapshots
Coverage	Code coverage with V8 or Istanbul providers	features-coverage
Test Context	Test fixtures, context.expect, test.extend for custom fixtures	features-context
Concurrency	Concurrent tests, parallel execution, sharding	features-concurrency
Filtering	Filter tests by name, file patterns, tags	features-filtering

Advanced

Topic	Description	Reference
Vi Utilities	vi helper: mock, spyOn, fake timers, hoisted, waitFor	advanced-vi
Environments	Test environments: node, jsdom, happy-dom, custom	advanced-environments
Type Testing	Type-level testing with expectTypeOf and assertType	advanced-type-testing
Projects	Multi-project workspaces, different configs per project	advanced-projects

AFENDA-HYBRID monorepo

Run tests from the repo root with pnpm filters or the root package.json scripts that delegate to @afenda/db.

Package	Role	Typical command
@afenda/db	PostgreSQL integration tests (Docker test DB, node env, pool: "forks", maxWorkers: 1)	pnpm test:db or pnpm --filter @afenda/db test:db
@afenda/ui-core	Primitives/patterns (no Vitest script in package; typecheck only)	—
@afenda/view-engine	React + jsdom, @vitejs/plugin-react	pnpm --filter @afenda/view-engine test
@afenda/erp-view-pack	Same stack	pnpm --filter @afenda/erp-view-pack test

Conventions: Vitest is declared as "vitest": "catalog:" in workspace packages so versions stay aligned. Config files live next to each package as vitest.config.ts. Database tests expect DATABASE_URL (default postgresql://postgres:postgres@localhost:5433/afenda_test); use root scripts like docker:test:start / test:db:recreate when the test DB is missing or stale.

Improving tests: Match each package’s existing include/setupFiles patterns; keep DB tests serial where migrations or shared DB state apply; use VITEST_MINIMAL=1 in @afenda/db for quieter CI output (see that package’s vitest.config.ts).