👷 Migrate unit tests to Vitest

.cursor/rules/test-driven-development.mdc

@@ -2,8 +2,8 @@
 description: Standards for Test-Driven Development in the Browser SDK project
 globs:
 tags:
-  - jasmine
-  - karma
+  - vitest
+  - browser-mode
 alwaysApply: true
 ---
 
@@ -29,17 +29,19 @@ touch packages/some-package/src/path/to/feature.spec.ts
 
 **Spec file must exist BEFORE implementation file**
 
-## 3. Spec Structure (Jasmine/Karma)
+## 3. Spec Structure (Vitest Browser Mode)
 
 ```typescript
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
 describe('FeatureName', () => {
 // Setup variables
 let feature: FeatureType
 let mockDependency: MockType
 
 beforeEach(() => {
     // Setup for each test
-    mockDependency = jasmine.createSpy()
+    mockDependency = vi.fn()
     feature = new FeatureName(mockDependency)
 
     // Use registerCleanupTask for cleanup

.cursor/rules/unit-test-best-practices.mdc

@@ -9,7 +9,7 @@ alwaysApply: false
 
 - **Run all unit tests**: `yarn test:unit`
 - **Run a specific spec file**: `yarn test:unit --spec <file-path>`
-- **Focus on specific tests**: Prepend `f` to `describe` and `it` (e.g., `fdescribe`, `fit`)
+- **Focus on specific tests**: Use `describe.only` or `it.only` temporarily
 
 ### Examples
 
@@ -33,15 +33,15 @@ yarn test:unit --spec "packages/browser-core/**/browser/*.spec.ts"
 #### Focus on Specific Tests
 ```typescript
 // Run only this describe block
-fdescribe('addEventListener', () => {
+describe.only('addEventListener', () => {
   // All tests in this block will run
   it('should add event listener', () => {})
   it('should remove event listener', () => {})
 })
 
 // Run only this single test
 describe('addEventListener', () => {
-  fit('should add event listener', () => {
+  it.only('should add event listener', () => {
     // Only this test will run
   })
 
@@ -64,24 +64,10 @@ describe('addEventListener', () => {
 ```bash
 # 1. Check test output for randomization seed
 yarn test:unit
-# Look for: "Randomized with seed 65781"
-
-# 2. Set seed in karma configuration
-# Edit test/unit/karma.base.conf.js:
-module.exports = {
-  // ... other config
-  client: {
-    jasmine: {
-      // ... other jasmine config
-      seed: 65781  // Use the seed from step 1
-    }
-  }
-}
-
-# 3. Run tests with the same order
-yarn test:unit
+# Look for: Running tests with seed "65781"
 
-# 4. Remove seed after debugging
+# 2. Run tests with the same order
+yarn test:unit --seed 65781
 ```
 
 ### File Organization
@@ -169,7 +155,7 @@ beforeEach(() => {
   clock = mockClock()
 })
 it('should handle delayed operations', () => {
-  const callback = jasmine.createSpy()
+  const callback = vi.fn()
   setTimeout(callback, 1000)
 
   clock.tick(1000) // Instant!

.github/dependabot.yml

@@ -17,6 +17,3 @@ updates:
     open-pull-requests-limit: 0
     commit-message:
       prefix: '👷'
-    ignore:
-      # update karma-webpack: RUM-3130
-      - dependency-name: 'karma-webpack'

.gitignore

@@ -41,3 +41,4 @@ test/e2e/.pinned-browsers/
 *.local.md
 .claude/settings.local.json
 .claude/worktrees/
+**/__screenshots__/

.gitlab-ci.yml

@@ -231,6 +231,7 @@ unit:
       junit: test-report/unit/*.xml
   script:
     - yarn
+    - yarn playwright install chromium --with-deps
     - yarn test:unit
   after_script:
     - node ./scripts/test/export-test-result.ts unit
@@ -314,13 +315,14 @@ unit-bs:
   interruptible: true
   parallel:
     matrix:
-      - BS_BROWSER: [edge, firefox, safari-desktop, chrome-desktop, chrome-mobile]
+      - BS_BROWSER: [edge, firefox, webkit-desktop, chrome-desktop]
   artifacts:
+    when: always
     reports:
       junit: test-report/unit-bs/*.xml
   script:
     - yarn
-    - node scripts/test/ci-bs.ts test:unit
+    - FORCE_COLOR=1 node scripts/test/ci-bs.ts test:unit
   after_script:
     - node ./scripts/test/export-test-result.ts unit-bs
 

AGENTS.md

@@ -76,7 +76,7 @@ test/
 ├── apps/            # Test apps for E2E and performance testing
 ├── e2e/             # Playwright E2E test scenarios
 ├── performance/     # Performance benchmarking tests
-└── unit/            # Karma/Jasmine unit test configuration
+└── unit/            # Vitest Browser Mode unit test configuration
 
 scripts/             # Build, deploy, release automation
 ```
@@ -97,8 +97,8 @@ For deeper context, see:
 
 ### Unit Tests
 
-- Test framework: Jasmine + Karma. Spec files co-located with implementation: `feature.ts` → `feature.spec.ts`
-- Focus tests with `fit()` / `fdescribe()`, skip with `xit()` / `xdescribe()`
+- Test framework: Vitest Browser Mode. Spec files co-located with implementation: `feature.ts` → `feature.spec.ts`
+- Focus tests with `it.only()` / `describe.only()`, skip with `it.skip()` / `describe.skip()`
 - Use `registerCleanupTask()` for cleanup, NOT `afterEach()`
 - Prefer `collectAsyncCalls(spy, n)` over `waitFor(() => spy.calls.count() > 0)` for waiting on spy calls
 - Don't destructure methods from `spy.calls` (e.g., `argsFor`, `mostRecent`) - use `calls.argsFor()` to avoid `@typescript-eslint/unbound-method` errors

LICENSE-3rdparty.csv

@@ -18,7 +18,6 @@ dev,@angular/core,MIT,Copyright (c) 2010-2024 Google LLC
 dev,@angular/platform-browser,MIT,Copyright (c) 2010-2024 Google LLC
 dev,@angular/router,MIT,Copyright (c) 2010-2024 Google LLC
 dev,@eslint/js,MIT,Copyright OpenJS Foundation and other contributors, <www.openjsf.org>
-dev,@jsdevtools/coverage-istanbul-loader,MIT,Copyright (c) 2015 James Messinger
 dev,@ngtools/webpack,MIT,Copyright (c) 2017 Google LLC
 dev,@playwright/test,Apache-2.0,Copyright Microsoft Corporation
 dev,@swc/core,Apache-2.0,Copyright (c) SWC Contributors
@@ -27,7 +26,6 @@ dev,@types/chrome,MIT,Copyright Microsoft Corporation
 dev,@types/busboy,MIT,Copyright Microsoft Corporation
 dev,@types/cors,MIT,Copyright Microsoft Corporation
 dev,@types/express,MIT,Copyright Microsoft Corporation
-dev,@types/jasmine,MIT,Copyright Microsoft Corporation
 dev,@types/node,MIT,Copyright Microsoft Corporation
 dev,@types/node-forge,MIT,Copyright Microsoft Corporation
 dev,@types/ws,MIT,Copyright Microsoft Corporation
@@ -39,6 +37,10 @@ dev,@wxt-dev/module-react,MIT,Copyright (c) 2023 Aaron
 dev,@vitejs/plugin-react,MIT,Copyright (c) 2019-present Evan You & Vite Contributors
 dev,@vitejs/plugin-vue,MIT,Copyright (c) 2019-present, Yuxi (Evan) You and Vite contributors
 dev,@microsoft/api-extractor,MIT,Copyright (c) Microsoft Corporation. All rights reserved.
+dev,@vitest/browser,MIT,Copyright (c) 2021-Present VoidZero Inc. and Vitest contributors
+dev,@vitest/browser-playwright,MIT,Copyright (c) 2021-Present VoidZero Inc. and Vitest contributors
+dev,@vitest/coverage-istanbul,MIT,Copyright (c) 2021-Present VoidZero Inc. and Vitest contributors
+dev,@vitest/eslint-plugin,MIT,Copyright (c) 2022 - PRESENT Verité Mugabo Makuza
 dev,@module-federation/enhanced,MIT, Copyright (c) 2020 ScriptedAlchemy LLC (Zack Jackson) Zhou Shaw (zhouxiao)
 dev,@vue/compiler-dom,MIT,Copyright (c) 2018-present, Yuxi (Evan) You
 dev,@vue/test-utils,MIT,Copyright (c) 2021-present vuejs
@@ -53,28 +55,18 @@ dev,emoji-name-map,MIT,Copyright 2016-19 Ionică Bizău <bizauionica@gmail.com>
 dev,eslint,MIT,Copyright JS Foundation and other contributors
 dev,eslint-plugin-import-x,MIT,Copyright (c) 2015 Ben Mosher
 dev,eslint-import-resolver-typescript,ISC,Copyright 2021 Alex Gorbatchev <alex.gorbatchev@gmail.com>
-dev,eslint-plugin-jasmine,MIT,Copyright (c) 2021 Tom Vincent
 dev,eslint-plugin-jsdoc,BSD-3-Clause,Copyright (c) 2018, Gajus Kuizinas (http://gajus.com/)
 dev,eslint-plugin-unicorn,MIT,Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (https://sindresorhus.com)
 dev,express,MIT,Copyright 2009-2014 TJ Holowaychuk 2013-2014 Roman Shtylman 2014-2015 Douglas Christopher Wilson
 dev,globals,MIT,Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com)
 dev,html-webpack-plugin,MIT,Copyright JS Foundation and other contributors
 dev,http-server,MIT,Copyright http-party contributors
-dev,jasmine-core,MIT,Copyright 2008-2017 Pivotal Labs
 dev,json-schema-to-typescript,MIT,
-dev,karma,MIT,Copyright 2011-2019 Google Inc.
-dev,karma-browserstack-launcher,MIT,Copyright 2011-2013 Google, Inc.
-dev,karma-chrome-launcher,MIT,Copyright 2011-2013 Google Inc.
-dev,karma-coverage-istanbul-reporter,MIT,Copyright 2017 Matt Lewis
-dev,karma-jasmine,MIT,Copyright 2011-2013 Google Inc.
-dev,karma-junit-reporter,MIT,Copyright (C) 2011-2013 Google, Inc.
-dev,karma-sourcemap-loader,MIT,Copyright 2013 Sergey Todyshev
-dev,karma-spec-reporter,MIT,Copyright 2015 Michael Lex
-dev,karma-webpack,MIT,Copyright JS Foundation and other contributors
 dev,minimatch,ISC,Copyright (c) Isaac Z. Schlueter and Contributors
 dev,next,MIT,Copyright (c) 2025 Vercel, Inc.
 dev,node-forge,BSD,Copyright (c) 2010, Digital Bazaar, Inc.
 dev,pako,MIT,(C) 2014-2017 Vitaly Puzrin and Andrey Tupitsin
+dev,playwright,Apache-2.0,Copyright Microsoft Corporation
 dev,prettier,MIT,Copyright James Long and contributors
 dev,puppeteer,Apache-2.0,Copyright 2017 Google Inc.
 dev,react-is,MIT,Copyright (c) Meta Platforms, Inc. and affiliates
@@ -92,6 +84,7 @@ dev,typescript,Apache-2.0,Copyright Microsoft Corporation
 dev,typescript-eslint,MIT,Copyright (c) 2019 typescript-eslint and other contributors
 dev,undici,MIT,Copyright (c) Matteo Collina and Undici contributors
 dev,vite,MIT,Copyright (c) 2019-present, VoidZero Inc. and Vite contributors
+dev,vitest,MIT,Copyright (c) 2021-Present VoidZero Inc. and Vitest contributors
 dev,vue,MIT,Copyright (c) 2018-present, Yuxi (Evan) You
 dev,nuxt,MIT,Copyright (c) 2016-present Nuxt Team
 dev,vue-router,MIT,Copyright (c) 2019-present Eduardo San Martin Morote

developer-extension/src/panel/components/tabs/eventsTab/computeFacetState.spec.ts

@@ -1,3 +1,4 @@
+import { describe, expect, it } from 'vitest'
 import type { RumActionEvent, RumResourceEvent } from '@datadog/browser-rum'
 import { FacetRegistry } from '../../../hooks/useEvents'
 import type { FacetValuesFilter } from '../../../hooks/useEvents'

developer-extension/src/panel/components/tabs/eventsTab/copyEvent.spec.ts

@@ -1,3 +1,4 @@
+import { describe, expect, it } from 'vitest'
 import type { TelemetryEvent } from '../../../../../../packages/browser-core/src/domain/telemetry'
 import type { LogsEvent } from '../../../../../../packages/browser-logs/src/logsEvent.types'
 import type { RumEvent } from '../../../../../../packages/browser-rum-core/src/rumEvent.types'

developer-extension/src/panel/flushEvents.spec.ts

@@ -1,13 +1,14 @@
+import { vi, beforeEach, describe, expect, it, type Mock } from 'vitest'
 import { registerCleanupTask } from '../../../packages/browser-core/test'
 import type { PageMayExitEvent } from '../../../packages/browser-core/src/browser/pageMayExitObservable'
 import { createPageMayExitObservable } from '../../../packages/browser-core/src/browser/pageMayExitObservable'
 import { flushScript } from './flushEvents'
 
 describe('flushEvents', () => {
-  let onExitSpy: jasmine.Spy<(event: PageMayExitEvent) => void>
+  let onExitSpy: Mock<(event: PageMayExitEvent) => void>
 
   beforeEach(() => {
-    onExitSpy = jasmine.createSpy()
+    onExitSpy = vi.fn()
     registerCleanupTask(createPageMayExitObservable().subscribe(onExitSpy).unsubscribe)
   })
 

developer-extension/src/panel/hooks/useEvents/eventFilters.spec.ts

@@ -1,3 +1,4 @@
+import { describe, expect, it } from 'vitest'
 import type { RumEvent } from '../../../../../packages/browser-rum-core/src/rumEvent.types'
 import type { LogsEvent } from '../../../../../packages/browser-logs/src/logsEvent.types'
 import { isSafari } from '../../../../../packages/browser-core/src/tools/utils/browserDetection'

developer-extension/src/panel/hooks/useEvents/facetRegistry.spec.ts

@@ -1,10 +1,12 @@
+import { beforeEach, describe, expect, it } from 'vitest'
 import { isChromium } from '../../../../../packages/browser-core/src/tools/utils/browserDetection'
 import { getAllFields } from './facetRegistry'
 
 describe('getAllFields', () => {
-  beforeEach(() => {
+  beforeEach((ctx) => {
     if (!isChromium()) {
-      pending('Extension only supported in chromium')
+      ctx.skip(true, 'extension only supported in Chromium')
+      return
     }
   })
 

developer-extension/tsconfig.json

@@ -7,7 +7,7 @@
     "moduleResolution": "bundler",
     "jsx": "react",
     "lib": ["ES2022", "DOM"],
-    "types": ["chrome", "react", "react-dom", "jasmine"],
+    "types": ["chrome", "react", "react-dom"],
     "skipLibCheck": true,
     "allowImportingTsExtensions": true,
     "noEmit": true

docs/TESTING.md

@@ -21,16 +21,16 @@ Use this strategy to test the integration on Real applications.
 ## Work with unit tests
 
 1. Write a unit test.
-2. Run only your tests by temporarily replacing `describe(...)` with `fdescribe(...)` or `it(...)` with `fit(...)`.
-3. Run `yarn test` in the project root. It will launch the tests in watch mode, and also expose [a local URL](http://localhost:9876/) that you can open in any browser.
-4. Look at your terminal to see your test results.
-5. For deeper investigation, open [the "debug" page](http://localhost:9876/debug.html#) to inspect test execution via the devtools.
+2. Run the spec directly with `yarn test:unit --spec packages/path/to/feature.spec.ts`.
+3. Use `it.only(...)` or `describe.only(...)` temporarily when you need to focus further. ESLint prevents focused tests from being checked in.
+4. Run `yarn test` for Vitest watch mode, or `yarn test:unit` for a single full run.
+5. Look at the terminal output; failure screenshots are written next to the failing spec under `__screenshots__`.
 
 ## Debug flaky unit tests
 
 Top-level `describe` blocks are run in a random order. Sometimes, an issue can only be reproduced with a given order. To reproduce a test run order:
 
-1. Check the `Randomized with seed XXXX` message from the test output.
+1. Check the `Running tests with seed "XXXX"` message from the test output.
 2. Run `yarn test:unit --seed XXXX`.
 
 ## Work with E2E tests

eslint.config.ts

@@ -1,11 +1,10 @@
 import eslint from '@eslint/js'
+import vitest from '@vitest/eslint-plugin'
 import { defineConfig } from 'eslint/config'
 import * as tseslint from 'typescript-eslint'
 import { importX } from 'eslint-plugin-import-x'
 import unicornPlugin from 'eslint-plugin-unicorn'
 import jsdocPlugin from 'eslint-plugin-jsdoc'
-// @ts-expect-error -- eslint-plugin-jasmine is not typed
-import jasmine from 'eslint-plugin-jasmine'
 import globals from 'globals'
 // eslint-disable-next-line local-rules/disallow-protected-directory-import
 import eslintLocalRules from './eslint-local-rules/index.ts'
@@ -36,6 +35,7 @@ export default defineConfig(
     ignores: [
       ...SCHEMAS.map((schema) => schema.typesPath),
       'packages/*/bundle',
+      'bundle',
       'packages/*/cjs',
       'packages/*/esm',
       'test/**/dist',
@@ -75,7 +75,7 @@ export default defineConfig(
       unicorn: unicornPlugin,
       'local-rules': { rules: eslintLocalRules as Record<string, any> },
       jsdoc: jsdocPlugin,
-      jasmine,
+      vitest,
     },
 
     languageOptions: {
@@ -246,7 +246,6 @@ export default defineConfig(
         },
       ],
 
-      'jasmine/no-focused-tests': 'error',
       'jsdoc/check-alignment': 'error',
       'jsdoc/check-indentation': 'error',
       'jsdoc/no-blank-blocks': 'error',
@@ -475,6 +474,16 @@ export default defineConfig(
     },
   },
 
+  {
+    files: [SPEC_FILES, 'packages/*/test/**/*.ts'],
+    rules: {
+      // vitest is a root devDependency, not listed in each sub-package
+      'import-x/no-extraneous-dependencies': 'off',
+      'vitest/no-focused-tests': 'error',
+      'vitest/no-identical-title': 'error',
+    },
+  },
+
   {
     files: ['packages/browser-core/src/tools/**/*.ts'],
     ignores: [SPEC_FILES],