Vitest v4 Upgrade

[ktun95]

v4 adds visual regression testing, which would allow us to replace playwright.

1. Remove coverage.all: false (BREAKING CHANGE)

Impact: 23 vitest config files across packages
Files affected: All configs with coverage settings (packages/ui-common, packages/header, packages/navbar, etc.)

The coverage.all option has been removed in v4. Your configs currently use:
coverage: {
include: ["src/*"],
all: false, // ❌ This option no longer exists
}

Action required: Remove the all: false line from all vitest configs. In v4, coverage only includes files loaded
during testing by default (which matches your previous all: false behavior).

Updated config should be:
coverage: {
include: ["src/*"],
// 'all' option removed - v4 default behavior matches old 'all: false'
}

Locations found at:

• packages/ui-common/vitest.config.ts:18
• packages/header/vitest.config.ts:12
• packages/header-mui5/vitest.config.ts:12
• packages/flex-layout-plugin/vitest.config.ts:12
• packages/google-analytics/vitest.config.ts:12
• packages/navbar/vitest.config.ts:13
• (and 17+ more config files)

Other Breaking Changes (Low/No Impact on Your Codebase)

2. Default Exclusions Simplified

Vitest v4 now only excludes node_modules and .git by default. Previously excluded patterns (dist, cypress, etc.)
are no longer automatic.

Impact: None detected in your configs
Recommendation: If you rely on default exclusions, consider adding explicit test.exclude patterns

3. globals: true Remains Valid

Your configs use globals: true extensively. This is still supported in v4, no changes needed.

4. Mock System Changes

• vi.fn().getMockName() returns vi.fn() instead of spy (may affect snapshots)
• invocationCallOrder now starts at 1 instead of 0

Impact: No usage found in your test files
Action: If you have snapshot tests on mocks, they may need updating after migration

Migration Checklist

1. ✅ Remove coverage.all: false from all 23 vitest.config.ts files
2. ✅ Update vitest dependency from 3.x to 4.x in all package.json files
3. ✅ Update @vitest/coverage-v8 from 3.x to 4.x
4. ⚠️ Run tests after upgrade to check for snapshot failures
5. ⚠️ Verify coverage reports work as expected

[coderabbitai]

A summary of the changes CodeRabbit can apply:

• Upgrade all Vitest-related test tooling to v4 across the monorepo by updating vitest (3.x→4.x) and @vitest/coverage-v8 where applicable in 32 package/app manifests, changing 25+ test setup imports from "@testing-library/jest-dom/matchers" to " @testing-library/jest-dom/vitest", bumping vite in apps/image-component-demo to 7.x, adding missing test deps to apps/stock-center package.json, and adding docs/VITEST_V4_MIGRATION.md.

• Upgrade Vitest to 4.x across the monorepo by updating package.json devDependencies (bump "vitest" to "4.x" and "@vitest/coverage-v8" to "4.x" in multiple apps/packages, bump "vite" to 7.x in apps/image-component-demo), add missing test libraries to apps/stock-center (vitest, @vitest/coverage-v8, @testing-library/react, @testing-library/user-event, @testing-library/react-hooks), replace all imports of "@testing-library/jest-dom/matchers" with "import * as matchers from '@testing-library/jest-dom/vitest'" in setup.ts files, and add docs/VITEST_V4_MIGRATION.md documenting the migration and verification steps.

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