👷 Migrate unit tests from Karma/Jasmine to Vitest by mormubis · Pull Request #4196 · DataDog/browser-sdk

mormubis · 2026-02-17T14:18:25Z

Motivation

Karma is deprecated. This migrates the full unit test suite to Vitest 4.x with browser mode (Playwright).

Changes

Most of the diff is mechanical spec file replacements (jasmine.createSpy() → vi.fn(), etc.). The interesting parts:

mockClock had to be rewritten because Vitest's vi.useFakeTimers fakes performance by default, which breaks every perf-related test. The toFake list now explicitly excludes it.

allJsonSchemas was using webpack's require.context to load schema files. Replaced with Vite's import.meta.glob.

BrowserStack needed bs-local.com as server host because Safari replaces localhost with its own domain, breaking cookie access in vitest's iframe. Same issue we already have with ServiceWorker tests in E2E. Cookie tests are still skipped on Safari because this alone doesn't fully fix it.

The unit-bs CI job needs Playwright installed with system deps (--with-deps) and 4 CPUs to handle 5 concurrent remote browsers without timing out.

vite@8.0.8 is pinned in the developer extension because @vitejs/plugin-react can't resolve vite/internal in newer patch versions.

3784 unit tests pass, 18628 BrowserStack tests across 5 browsers.

Test instructions

yarn test:unit
yarn typecheck
yarn lint

Checklist

Tested locally
Tested on staging
Added unit tests for this change.
Added e2e/integration tests for this change.
Updated documentation and/or relevant AGENTS.md file

github-actions · 2026-02-17T14:18:39Z

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

cit-pr-commenter-54b7da · 2026-02-17T15:57:28Z

Bundles Sizes Evolution

📦 Bundle Name	Base Size	Local Size	𝚫%	Status
Rum	172.61 KiB	172.61 KiB	0.00%	✅
Rum Profiler	8.22 KiB	8.22 KiB	0.00%	✅
Rum Recorder	21.14 KiB	21.14 KiB	0.00%	✅
Logs	54.58 KiB	54.58 KiB	0.00%	✅
Rum Slim	130.44 KiB	130.44 KiB	0.00%	✅
Worker	22.96 KiB	22.96 KiB	0.00%	✅

mormubis · 2026-05-05T15:04:31Z

+  },
+
+  test: {
+    browser: {


Browser mode with Playwright. Locally it runs headless Chromium. On BrowserStack, Playwright connects to remote browsers via WebSocket (wss://cdp.browserstack.com/playwright), so the old browser versions (Chrome 63, Edge 80, etc.) are real browsers hosted by BrowserStack, not local Playwright binaries. The aliases mirror tsconfig.base.json so vitest resolves packages the same way TypeScript does.

mormubis · 2026-05-05T15:04:40Z

+  // AND so performance.timing.navigationStart remains accessible.
+  // When performance IS faked, @sinonjs/fake-timers replaces the object and our
+  // override silently fails (the fake performance.now() starts at 0).
+  vi.useFakeTimers({


performance is excluded from toFake. If we fake it, performance.now() returns fake time but the browser's internal performance observer still uses real time. Breaks every perf-related test.

mormubis · 2026-05-05T15:04:42Z

+  mostRecent(): { args: Parameters<F>; returnValue: ReturnType<F> }
+}
+
+export function collectAsyncCalls<F extends (...args: any[]) => any>(


Vitest equivalent of the old Jasmine calls.all() pattern. Wraps a vi.fn() and resolves a promise once the expected number of calls is reached.

mormubis · 2026-05-05T15:04:43Z

+/// <reference types="vite/client" />
+// Load all JSON schema files from the rum-events-format submodule.
+// Uses Vite's import.meta.glob (replaces webpack's require.context).
+const schemaModules = import.meta.glob('../../../rum-events-format/schemas/**/*.json', { eager: true })


require.context → import.meta.glob. Same result, Vite API instead of webpack.

…convert new debugger specs to Vitest - Add @datadog/js-core/time alias to vitest.config.ts - Move time-related imports from @datadog/browser-core to @datadog/js-core/time across ~70 files - Convert display.spec.ts, probes.spec.ts (new from main) to Vitest - Re-convert deliveryApi.spec.ts and api.spec.ts from main (complete rewrite) - Fix allJsonSchemas.js require.context (removed .js/.d.ts, kept .ts with import.meta.glob) - Fix getTimeStamp → toTimeStamp rename - Fix getNavigationStart → getTimeOrigin rename - Remove supportPerformanceTimingEvent guard (removed on main)

…vite 7 compatibility Vitest brings vite 7.x which conflicts with @vitejs/plugin-react 6.x (requires vite 8). Pin to 5.2.0 via Yarn resolution for wxt compatibility.

Aliases were pointing to old directory names (packages/core/, packages/rum-core/, etc.) instead of the renamed directories (packages/browser-core/, packages/browser-rum-core/, etc.). Also adds the missing @datadog/js-core/time alias. The old paths worked by accident via yarn workspace symlink fallback.

# Conflicts: # packages/browser-rum-core/src/browser/locationChangeObservable.spec.ts # yarn.lock

Four spec files had Jasmine patterns after the merge with main: - addEventListener.spec.ts: jasmine.createSpy().and.throwError - cookieAccess.spec.ts: jasmine.createSpy().and.throwError - reportObservable.spec.ts: jasmine.Spy cast + .and.throwError - eventBridge.spec.ts: toBeTrue/toBeFalse/spyOn (new wildcard tests)

Main added instrumentConstructor utility (#4714) with Jasmine tests. Converted all patterns: jasmine.createSpy → vi.fn, jasmine.any → expect.any, .calls.mostRecent().args → .mock.calls, toBeTrue/toBeFalse → toBe(true/false), toHaveBeenCalledOnceWith → toHaveBeenCalledOnce + toHaveBeenCalledWith.

Vitest supports ctx.skip(condition, reason) to explain why a test is skipped. Added descriptive reasons to all 34 bare ctx.skip() calls across the test suite.

# Conflicts: # packages/browser-core/src/domain/contexts/accountContext.spec.ts # packages/browser-core/src/domain/contexts/tabContext.spec.ts # packages/browser-core/src/tools/abstractHooks.spec.ts # packages/browser-logs/src/domain/assembly.spec.ts # packages/browser-rum-core/src/domain/action/actionCollection.spec.ts # packages/browser-rum-core/src/domain/contexts/ciVisibilityContext.spec.ts # packages/browser-rum-core/src/domain/contexts/displayContext.spec.ts # packages/browser-rum-core/src/domain/contexts/pageStateHistory.spec.ts # packages/browser-rum-core/src/domain/contexts/sessionContext.spec.ts # packages/browser-rum-core/src/domain/contexts/sourceCodeContext.spec.ts # packages/browser-rum-core/src/domain/view/viewCollection.spec.ts # packages/browser-rum/src/boot/profilerApi.spec.ts

# Conflicts: # developer-extension/src/panel/flushEvents.spec.ts # package.json # packages/browser-core/src/browser/addEventListener.spec.ts # packages/browser-core/src/browser/cookieAccess.spec.ts # packages/browser-core/src/browser/pageMayExitObservable.spec.ts # packages/browser-core/src/browser/xhrObservable.spec.ts # packages/browser-core/src/domain/configuration/configuration.spec.ts # packages/browser-core/src/domain/context/storeContextManager.spec.ts # packages/browser-core/src/domain/report/reportObservable.spec.ts # packages/browser-debugger/src/domain/probes.spec.ts # packages/browser-rum-core/src/browser/locationChangeObservable.spec.ts # packages/browser-rum-core/src/browser/performanceObservable.spec.ts # packages/browser-rum-core/src/browser/viewportObservable.spec.ts # packages/browser-rum-core/src/domain/contexts/ciVisibilityContext.spec.ts # packages/browser-rum-core/src/domain/view/bfCacheSupport.spec.ts # packages/browser-rum-core/src/domain/view/viewMetrics/trackFirstContentfulPaint.spec.ts # packages/browser-rum/src/domain/deflate/deflateEncoder.spec.ts # packages/browser-rum/src/domain/record/trackers/trackFocus.spec.ts

CI has a newer eslint-plugin-unicorn version that supports this option. Local version didn't, causing the initial removal.

…Hook API changes - package.json: re-added vitest deps/scripts/resolutions on top of main's changes - allJsonSchemas.ts: updated glob path from submodule to node_modules/@datadog/rum-events-format - profiler.spec.ts: took main's removal of findTrackedSessionSpy, converted toBeTrue - tsconfig.default.json: removed jasmine types, added vitest.bs.config.ts exclusion - vitest configs: updated js-core/time alias to src/entries/time

# Conflicts: # package.json # packages/browser-rum-core/test/allJsonSchemas.js # packages/browser-rum/src/domain/profiling/profiler.spec.ts # tsconfig.default.json # yarn.lock

- Add toHaveLength() guards alongside expect.arrayContaining() where jasmine.arrayWithExactContents was converted (trackClickActions, configuration specs) - Convert bare return to ctx.skip() in serializeNode.stylesheet.spec.ts

- bs-wrapper: anchor failure regex to Vitest summary format (`/\d+ failed |/`) to avoid false positives from test console output like '3 failed retries' - registerCleanupTask: await async cleanup tasks instead of fire-and-forget - allJsonSchemas: throw if no schemas loaded (catches silent glob path breakage) - Remove dead browserstack.keepalive.ts (never wired into setupFiles) - Fix TaskContext → TestContext type import in stylesheet spec

- reportObservable: double-registration would fire spy twice silently - deliveryApi: double-logging of probe failures would go undetected - deflateEncoder: test named 'do not notify twice' now asserts count

Matches vitest.config.ts — prevents CJS modules that check `global` from silently breaking on BrowserStack only.

Resolves conflicts from js-core/assembly, js-core/util, js-core/monitor entry points and profiler transport extraction. Converts new spec files from Jasmine to Vitest API. Adds missing vitest aliases for new js-core subpath imports.

Resolves conflicts from createBatch API refactor (reportError string signature, forceFlush), prototype pollution guards in mergeInto, debugger init version tests, and dep bumps. Converts new Jasmine patterns to Vitest API in auto-merged files.

Resolves conflicts from endpointBuilder/intakeSites move to @datadog/js-core/transport. Adds js-core/transport alias to both vitest configs. Converts import paths in 8 spec files + test helper.

bs-wrapper.ts: ANSI escape codes from FORCE_COLOR broke failure detection — the regex /\d+ failed \|/ didn't match colored output like '9 failed\x1b[39m |'. Strip ANSI before matching. cookieAccess.spec.ts: CookieStore API tests crashed with TypeError when globalObject.cookieStore was undefined (Jasmine's pending() inside setup() skipped the enclosing it(), but Vitest doesn't). Added beforeEach ctx.skip for the CookieStore describe block.

mormubis force-pushed the adlrb/vitest branch 5 times, most recently from 319576e to 02e30e1 Compare February 20, 2026 10:19

mormubis force-pushed the adlrb/vitest branch 18 times, most recently from 051c55a to 23d1a16 Compare April 30, 2026 21:16

mormubis force-pushed the adlrb/vitest branch from e48694e to 9f695e5 Compare May 5, 2026 13:29

mormubis commented May 5, 2026

View reviewed changes

mormubis force-pushed the adlrb/vitest branch from 22f3352 to d30d518 Compare June 9, 2026 10:44

mormubis added 10 commits June 9, 2026 16:24

🐛 Fix developer-extension build: pin @vitejs/plugin-react to 5.x for …

4eebd36

…vite 7 compatibility Vitest brings vite 7.x which conflicts with @vitejs/plugin-react 6.x (requires vite 8). Pin to 5.2.0 via Yarn resolution for wxt compatibility.

Merge remote-tracking branch 'origin/main' into adlrb/vitest

80e1bef

# Conflicts: # packages/browser-rum-core/src/browser/locationChangeObservable.spec.ts # yarn.lock

✨ Add skip reasons to all ctx.skip() calls

30acad4

Vitest supports ctx.skip(condition, reason) to explain why a test is skipped. Added descriptive reasons to all 34 bare ctx.skip() calls across the test suite.

🐛 Restore checkDirectories: false in unicorn/filename-case rules

ca5c958

CI has a newer eslint-plugin-unicorn version that supports this option. Local version didn't, causing the initial removal.

mormubis force-pushed the adlrb/vitest branch from a3afe56 to 40e5dda Compare June 16, 2026 09:32

mormubis added 6 commits June 16, 2026 11:51

Merge remote-tracking branch 'origin/main' into adlrb/vitest

41a2792

# Conflicts: # package.json # packages/browser-rum-core/test/allJsonSchemas.js # packages/browser-rum/src/domain/profiling/profiler.spec.ts # tsconfig.default.json # yarn.lock

🔧 Fix weakened assertions and missing ctx.skip

e5a21a1

- Add toHaveLength() guards alongside expect.arrayContaining() where jasmine.arrayWithExactContents was converted (trackClickActions, configuration specs) - Convert bare return to ctx.skip() in serializeNode.stylesheet.spec.ts

🔧 Restore toHaveBeenCalledTimes(1) where once-semantics matter

b993bed

- reportObservable: double-registration would fire spy twice silently - deliveryApi: double-logging of probe failures would go undetected - deflateEncoder: test named 'do not notify twice' now asserts count

🔧 Add missing global: 'globalThis' define to BS config

406be41

Matches vitest.config.ts — prevents CJS modules that check `global` from silently breaking on BrowserStack only.

mormubis force-pushed the adlrb/vitest branch from f84884d to 9b01784 Compare June 19, 2026 12:43

mormubis force-pushed the adlrb/vitest branch from 04ad2be to ecdd4ec Compare June 29, 2026 08:03

🔀 Merge main: endpointBuilder to js-core, Playwright 1.61, dep bumps

5c2b96c

Resolves conflicts from endpointBuilder/intakeSites move to @datadog/js-core/transport. Adds js-core/transport alias to both vitest configs. Converts import paths in 8 spec files + test helper.

mormubis force-pushed the adlrb/vitest branch 6 times, most recently from aa625fe to 4e06cf3 Compare July 2, 2026 09:37

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👷 Migrate unit tests from Karma/Jasmine to Vitest - #4196

👷 Migrate unit tests from Karma/Jasmine to Vitest#4196
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