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[No QA] Run all Jest tests through the OXC transformer - #100438

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[No QA] Run all Jest tests through the OXC transformer#100438
roryabraham wants to merge 16 commits into
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rory/oxc-jest-all-tests

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@roryabraham roryabraham commented Sep 5, 2026 •
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Explanation of Change

Regular Jest still used babel-jest for every JS/TS file, while Reassure already used the OXC transformer. The split existed because jest.mock has to be hoisted above generated require() calls.

This PR routes all Jest runs through config/babel/oxcJestTransformer.js:

  1. OXC compiles TS/JSX (React Compiler on app sources only; skipped for tests/, jest/, and __mocks__/).
  2. A small Babel pass emits loose CommonJS, lowers import(), and runs babel-plugin-jest-hoist.
  3. babel-jest remains the fallback for Flow in node_modules.

strictMode: false is required so existing tests that assign to getter-only native mock properties (e.g. AppState.currentState) keep working. The CI Jest cache key now also hashes jest.config.js and the transformer files.

jest-expo's haste map uses defaultPlatform: 'ios', so @components/ImageSVG resolves to index.ios.tsx which imports expo-image. That package has no jest-expo mock, so jest/setup.ts stubs it.

Benchmark (local, --maxWorkers=6)

Re-run on merged head c7a8258 with Node 26.5.0, npm 11.17.0, and --maxWorkers=6. Cold runs started from a cleared Jest cache.

Suite babel-jest (before) OXC (after) Delta
tests/unit/hooks cold 45.8s Jest / 59.0s wall 44.8s Jest / 57.7s wall −2% / −2%
tests/unit/hooks warm 30.5s Jest / 42.4s wall 35.4s Jest / 47.7s wall +16% / +12%
3 UI tests cold 42.9s Jest / 53.4s wall 36.2s Jest / 48.8s wall −16% / −9%
3 UI tests warm 12.4s Jest / 30.6s wall 9.9s Jest / 21.6s wall −21% / −29%

Correctness checks on the OXC path: tests/unit/hooks (157 suites / 1635 tests), tests/actions (83 / 2293), tests/navigation (48 / 564), plus bun test ./tests/tooling/oxcTransformer.test.ts.

Fixed Issues

$
PROPOSAL:

Tests

// TODO: The human co-author must fill out the tests you ran before marking this PR as "ready for review"
// Please describe what tests you performed that validates your changed worked.

Offline tests

QA Steps

// TODO: The human co-author must fill out the QA tests you ran before marking this PR as "ready for review".
// Please describe what QA needs to do to validate your changes and what areas do they need to test for regressions.

PR Author Checklist

  • I linked the correct issue in the ### Fixed Issues section above
  • I wrote clear testing steps that cover the changes made in this PR
    • I added steps for local testing in the Tests section
    • I added steps for the expected offline behavior in the Offline steps section
    • I added steps for Staging and/or Production testing in the QA steps section
    • I added steps to cover failure scenarios (i.e. verify an input displays the correct error message if the entered data is not correct)
    • I turned off my network connection and tested it while offline to ensure it matches the expected behavior (i.e. verify the default avatar icon is displayed if app is offline)
    • I tested this PR with a High Traffic account against the staging or production API to ensure there are no regressions (e.g. long loading states that impact usability).
  • I included screenshots or videos for tests on all platforms
  • I ran the tests on all platforms & verified they passed on:
    • Android: Native
    • Android: mWeb Chrome
    • iOS: Native
    • iOS: mWeb Safari
    • MacOS: Chrome / Safari
  • I verified there are no console errors (if there's a console error not related to the PR, report it or open an issue for it to be fixed)
  • I followed proper code patterns (see Reviewing the code)
    • I verified that comments were added to code that is not self explanatory
    • I verified that any new or modified comments were clear, correct English, and explained "why" the code was doing something instead of only explaining "what" the code was doing.
    • I verified any copy / text that was added to the app is grammatically correct in English. It adheres to proper capitalization guidelines (note: only the first word of header/labels should be capitalized), and is either coming verbatim from figma or has been approved by marketing (in order to get marketing approval, ask the Bug Zero team member to add the Waiting for copy label to the issue)
  • If a new code pattern is added I verified it was agreed to be used by multiple Expensify engineers
  • I followed the guidelines as stated in the Review Guidelines
  • I tested other components that can be impacted by my changes (i.e. if the PR modifies a shared library or component like Avatar, I verified the components using Avatar are working as expected)
  • If a new CSS style is added I verified that:
    • A similar style doesn't already exist
    • The style can't be created with an existing StyleUtils function (i.e. StyleUtils.getBackgroundAndBorderStyle(theme.componentBG))
  • If new assets were added or existing ones were modified, I verified that:
    • The assets are optimized and compressed (for SVG files, run npm run compress-svg)
    • The assets load correctly across all supported platforms.
  • If the PR modifies code that runs when editing or sending messages, I tested and verified there is no unexpected behavior for all supported markdown - URLs, single line code, code blocks, quotes, headings, bold, strikethrough, and italic.
  • If the PR modifies a generic component, I tested and verified that those changes do not break usages of that component in the rest of the App (i.e. if a shared library or component like Avatar is modified, I verified that Avatar is working as expected in all cases)
  • If the PR modifies a component related to any of the existing Storybook stories, I tested and verified all stories for that component are still working as expected.
  • If the PR modifies a component or page that can be accessed by a direct deeplink, I verified that the code functions as expected when the deeplink is used - from a logged in and logged out account.
  • If the PR modifies the UI (e.g. new buttons, new UI components, changing the padding/spacing/sizing, moving components, etc) or modifies the form input styles:
    • I verified that all the inputs inside a form are aligned with each other.
    • I added Design label and/or tagged @Expensify/design so the design team can review the changes.
  • I added unit tests for any new feature or bug fix in this PR to help automatically prevent regressions in this user flow.
  • If the main branch was merged into this PR after a review, I tested again and verified the outcome was still expected according to the Test steps.

Screenshots/Videos

Android: Native
Android: mWeb Chrome
iOS: Native
iOS: mWeb Safari
MacOS: Chrome / Safari

@roryabraham
Run all Jest tests through the OXC transformer
f267e33 
babel-jest was still transforming the regular suite so jest.mock stayed
hoisted. Route every JS/TS file through OXC, then a small Babel pass for
loose CJS, import() lowering, and mock hoisting. Keep babel-jest only as
the node_modules/Flow fallback.
@roryabraham roryabraham self-assigned this Sep 5, 2026
@roryabraham
roryabraham requested a review from a team September 5, 2026 01:16
@roryabraham
Lower const/let in the OXC Jest CJS pass
2c0cc38 
CI failed with TDZ on circular imports and jest.mock factories that
closed over const. Babel used to rewrite those to var; restore that
with plugin-transform-block-scoping so existing tests keep working.
@roryabraham

roryabraham commented Sep 6, 2026

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HOLD: esbuild CJS still TDZs on the PersistedRequests ↔ SequentialQueue cycle (initializationCallback). That is production module graph, not a test rewrite.

#99910 (import/no-cycle part 3) cuts Log → Network (post → MainQueueStore.enqueue), which is the edge that pulls SequentialQueue into Log's import graph. Once that lands, we should re-check whether the cycle is gone before merging this.

Test-side esbuild CJS mismatches (mock-factory TDZ, jest.spyOn on named exports, RN mock getter spread) are being migrated in this PR.

@roryabraham roryabraham changed the title Run all Jest tests through the OXC transformer [No QA] Run all Jest tests through the OXC transformer Sep 7, 2026
@roryabraham
Merge remote-tracking branch 'origin/main' into rory/oxc-jest-all-tests
4c82bcb
@roryabraham
Fix oxfmt and knip on the OXC Jest transformer
08f3066 
Collapse CJS_PLUGINS to satisfy oxfmt, and ignore the Babel plugins
the transformer loads by string name so knip does not flag them as
unlisted.
@roryabraham
Use esbuild for CJS in the OXC Jest transformer
fa9328d 
Babel was only needed to hoist jest.mock. Emit CJS and lower import()
with esbuild, then run a hoist-only Babel pass on files that call
jest.mock. Drop the unused Babel CJS plugin knip ignores.
@roryabraham
Hoist jest.mock without Babel in the OXC Jest transformer
9dc840b 
OXC and esbuild do not hoist jest.mock above require(). Splice
top-level jest.mock/unmock calls with a scanner instead of a Babel
AST pass so the CJS path stays native.
@roryabraham
Hoist jest.mock with oxc-parser instead of a scanner
01ffa0a 
OXC still does not hoist jest.mock. Parse the esbuild CJS output with
oxc-parser and splice top-level jest.mock/unmock spans above require()
so Jest intercepts them without Babel or a hand-rolled lexer.
@roryabraham
Fix Jest typecheck after switching API.write spies to jest.mocked
ab90c2f 
DomainTest's mockImplementation must return a Promise. DuplicateTest
must treat write spy calls as unknown[][] so the command type guard
can narrow parameters off the API write union.
@roryabraham
Restore Babel loose CJS after OXC for Jest
4b26204 
esbuild CJS live-binding getters and leftover const/let caused TDZ
and slower module load. Emit CJS with Babel loose modules, lower
import(), and hoist jest.mock after OXC strips TS/JSX. Drop oxc-parser.
@roryabraham
Fix Jest ExpoImage load and drop esbuild test rewrites
6f63e8c 
jest-expo haste uses defaultPlatform ios, so ImageSVG resolves to
index.ios.tsx which imports expo-image. Stub expo-image in setup so
UI suites can load. Revert the esbuild-era jest.spyOn / mock rewrites
now that Babel loose CJS is back.
@melvin-bot

melvin-bot Bot commented Sep 7, 2026

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npm has a package.json file and a package-lock.json file. It seems you updated one without the other, which is usually a sign of a mistake. If you are updating a package make sure that you update the version in package.json then run npm install

@roryabraham
Mock Expo Store Review in Jest
0d381b3
@roryabraham
Keep string SVG sources in the Jest expo-image mock
b3687b4 
CopilotPageTest looks for mocked icon names like icon-three-dots in
the tree. Returning null from expo-image hid those sources on the
jest-expo iOS ImageSVG path.
@roryabraham
Force Jest workers to exit after CI shards
bffaa33 
Shard 7 now keeps leftover handles after full-App tests survive
ExpoImage/StoreReview, so CI never finishes. --forceExit matches
local shard 7, which already passed.
@roryabraham
fix: clean up Jest app timers
01470f2 
Cancel pending Network queue starts during teardown so Jest workers exit without --forceExit.
@roryabraham
Merge remote-tracking branch 'origin/main' into rory/oxc-jest-all-tests
c7a8258 
# Conflicts:
#	tests/ui/MoneyRequestReportPreview.test.tsx
@roryabraham
ci: reduce OXC Jest worker concurrency
19171ac 
Coverage shards exhaust self-hosted runner resources with six native-transform workers. Use four workers so the runner remains responsive.
@codecov

codecov Bot commented Sep 9, 2026 •
edited by github-actions Bot
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Codecov Report

✅ Changes either increased or maintained existing code coverage, great job!

Files with missing lines Coverage Δ
src/libs/Network/index.ts 100.00% <100.00%> (+7.14%) ⬆️
... and 5507 files with indirect coverage changes

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