vitest

name	vitest
description	Vitest unit testing — Vite-powered, Jest-compatible. Use when writing tests, mocking, configuring coverage, or working with test filtering and fixtures.
group	brana
keywords	["vitest","testing","vite","jest","mocking","coverage","typescript","esm","fixtures","snapshots"]
allowed-tools	["Read","Write","Edit","Bash","Glob","Grep","Agent"]
status	experimental
source	https://github.com/supabase/supabase @vitest
acquired	2026-04-30
quarantine	false

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

The skill is based on Vitest 3.x, generated at 2026-01-28.

Core

Topic	Description	Reference
Configuration	Vitest and Vite config integration, defineConfig usage	core-config (upstream references/core-config.md, not installed locally)
CLI	Command line interface, commands and options	core-cli (upstream references/core-cli.md, not installed locally)
Test API	test/it function, modifiers like skip, only, concurrent	core-test-api (upstream references/core-test-api.md, not installed locally)
Describe API	describe/suite for grouping tests and nested suites	core-describe (upstream references/core-describe.md, not installed locally)
Expect API	Assertions with toBe, toEqual, matchers and asymmetric matchers	core-expect (upstream references/core-expect.md, not installed locally)
Hooks	beforeEach, afterEach, beforeAll, afterAll, aroundEach	core-hooks (upstream references/core-hooks.md, not installed locally)

Features

Topic	Description	Reference
Mocking	Mock functions, modules, timers, dates with vi utilities	features-mocking (upstream references/features-mocking.md, not installed locally)
Snapshots	Snapshot testing with toMatchSnapshot and inline snapshots	features-snapshots (upstream references/features-snapshots.md, not installed locally)
Coverage	Code coverage with V8 or Istanbul providers	features-coverage (upstream references/features-coverage.md, not installed locally)
Test Context	Test fixtures, context.expect, test.extend for custom fixtures	features-context (upstream references/features-context.md, not installed locally)
Concurrency	Concurrent tests, parallel execution, sharding	features-concurrency (upstream references/features-concurrency.md, not installed locally)
Filtering	Filter tests by name, file patterns, tags	features-filtering (upstream references/features-filtering.md, not installed locally)

Advanced

Topic	Description	Reference
Vi Utilities	vi helper: mock, spyOn, fake timers, hoisted, waitFor	advanced-vi (upstream references/advanced-vi.md, not installed locally)
Environments	Test environments: node, jsdom, happy-dom, custom	advanced-environments (upstream references/advanced-environments.md, not installed locally)
Type Testing	Type-level testing with expectTypeOf and assertType	advanced-type-testing (upstream references/advanced-type-testing.md, not installed locally)
Projects	Multi-project workspaces, different configs per project	advanced-projects (upstream references/advanced-projects.md, not installed locally)

Project-specific notes (proyecto_anita)

• Run vitest from services/frontend-v2/, not repo root — @/ alias resolves relative to vitest.config.ts directory (see feedback_vitest_cwd_alias.md)
• Mock @/lib/supabase/client before any import that transitively reaches it (see feedback_supabase_mock_at_import.md)