test(app-check): migrate app-check to Vitest

[Manvi1203]

Summary

Migrates @firebase/app-check unit tests from legacy Karma (Mocha / Chai / Sinon) to Vitest (Browser Chromium via Playwright).

Description

• Runner & Config: Replaced karma.conf.js with vitest.config.mjs extending config/vitest.base.mjs. Configured browser runner targeting Chromium via Playwright with defensive project filtering (if (config.test?.projects)). Updated test/setup.ts with global afterEach teardown (vi.useRealTimers(), vi.resetAllMocks(), vi.restoreAllMocks()).
• Target Environment: @firebase/app-check relies on browser APIs (self.grecaptcha, IndexedDB, localStorage, DOM <script> injection, document.hasFocus, page visibility/proactive refresh timers). All 8 unit test suites run in the browser project via @vitest/browser-playwright.
• Assertions & Lifecycle: Converted legacy Chai assertions (expect(...).to.equal, .to.deep.equal, .to.be.true, .to.be.rejectedWith, .to.throw) to native Vitest matchers (.toBe(), .toEqual(), .toBe(true), .rejects.toThrow(), .toThrow()). Converted Mocha's done callback in src/internal-api.test.ts to Promise-based async execution. Standardized afterEach cleanup for globals (self.grecaptcha, self.FIREBASE_APPCHECK_DEBUG_TOKEN).
• Mocks, Spies & Timers: Converted Sinon stubs, spies, and fake timers (sinon.stub, sinon.spy, sinon.useFakeTimers) to native Vitest utilities (vi.fn(), vi.spyOn(), vi.useFakeTimers()). Used vi.mock('...', { spy: true }) in api.test.ts, debug.test.ts, internal-api.test.ts, providers.test.ts, and storage.test.ts so sealed ESM module exports (./client, ./indexeddb, ./storage, ./recaptcha, ./debug, ./util, ./internal-api, @firebase/util) can be spied and overridden per test via vi.spyOn(...) while keeping their original implementations active by default.
• Module Augmentation: Updated declare module '@firebase/component' to declare module '@firebase/component/dist/src/types' in src/index.ts and src/public-types.ts so Vite's ESM resolver properly merges NameServiceMapping for 'app-check' and 'app-check-internal'.
• Package Scripts: Updated package.json scripts (test, test:ci, test:browser, test:browser:debug) to run Vitest and removed legacy Karma scripts (test:karma, test:karma:debug).

Performance

• Baseline (Karma + Webpack): ~12–15s total duration
• Vitest (Unit Tests): ~2.5s (8 test files, 111 tests passed)

[changeset-bot]

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Latest commit: 88362b6

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[gemini-code-assist]

Code Review

This pull request migrates the @firebase/app-check package's test suite from Karma, Mocha, Chai, and Sinon to Vitest. This involves updating configuration files, package scripts, and test files to use Vitest's APIs and assertions. The review feedback points out several remaining instances of legacy Chai .to.equal assertions in internal-api.test.ts that should be updated to Vitest's .toBe() matcher.

[Manvi1203]

/gemini review

[gemini-code-assist]

Code Review

This pull request migrates the app-check package's test suite from Karma, Mocha, Chai, and Sinon to Vitest, updating configuration files, test scripts, and test assertions accordingly. It also refactors some type-only exports to use export type. The review feedback identifies several opportunities to improve test isolation and robustness: specifically, ensuring mock wrappers for readDebugTokenFromIndexedDB correctly forward arguments to the underlying implementation, and properly cleaning up global variables like self.FIREBASE_APPCHECK_DEBUG_TOKEN and self.grecaptcha in afterEach blocks to prevent test pollution.