Switch from Jest to vitest

.github/workflows/pr.yml

@@ -8,7 +8,7 @@ jobs:
     steps:
       - uses: actions/setup-node@v7
         with:
-          node-version: 18
+          node-version: 24
       - uses: actions/checkout@v7
       - name: npm install
         run: npm install

AGENTS.md

@@ -145,50 +145,48 @@ GitForWindowsHelper/        # the Azure Function code
 ├── https-request.js / search.js / gently.js / org.js
 └── validate-github-webhook.js
 
-__tests__/                  # Jest tests for the App (index + component-updates)
+__tests__/                  # Vitest tests (index + component-updates)
 .github/workflows/deploy.yml # deploys the Function to Azure on push to main
-embargoed-builds/           # SEPARATE git worktree (see below) -- do not edit here
 ```
 
-## The `embargoed-builds` Worktree
+## Secondary worktrees
 
-`embargoed-builds/` is **not** part of the `main` branch. It is a separate
-long-lived branch (`embargoed-builds`) that is typically checked out as a
-[git worktree](https://git-scm.com/docs/git-worktree) nested in the
-working directory. It is a parallel variant of this App used to build
-**embargoed security releases**: it deploys to private Azure Blob Storage
-(`wingit.blob.core.windows.net`) instead of the public `pacman-repo`, and
-relies on self-hosted Windows/ARM64 runners.
+There might be `vitest/`, `embargoed-builds/` and other worktrees that are
+**not** part of the `main` branch. These are separate, and not to be
+touched by you.
 
 Consequences for agents:
 
-- When working on `main`, **do not edit files under `embargoed-builds/`**.
-  It belongs to a different branch and is maintained separately; the two
-  variants are reconciled deliberately, not by editing both at once.
-- Because Jest's default `testMatch` is `**/__tests__/**`, running
-  `npm test` from the repo root also collects
-  `embargoed-builds/__tests__/` when that worktree is present (you will
-  see four suites instead of two). To run only this App's tests, scope it:
-  `npx jest __tests__/`.
+- When working on `main`, **do not edit files under `vitest/**`,
+  `embargoed-builds/**` or any other nested worktree. They belong to
+  separate work, and you must focus on the current work.
+- Vitest collects only root `__tests__/*.test.js` files, so `npm test`
+  does not collect tests from any nested worktree.
 
 ## Building, Testing and Linting
 
-There is no build step; the Function is deployed as-is. Verified commands:
+There is no build step; the Function is deployed as-is. Use Node.js 24 for
+test tooling, matching the PR check workflow. Verified commands:
 
 - `npm run lint` — ESLint over `**/*.js` (config in `eslint.config.js`).
 - `npm run lint:fix` — ESLint with `--fix`.
-- `npm test` — Jest. To restrict to this App (excluding the
-  `embargoed-builds` worktree), use `npx jest __tests__/`.
+- `npm test` -- Vitest, in non-watch mode, scoped to this App's tests.
+- `npm test -- __tests__/index.test.js` -- Run only the webhook suite.
 
 Always run lint and tests before committing.
 
 ## Testing Conventions
 
+Import test APIs explicitly from `vitest`; the Function remains CommonJS.
+Use `createMockRequire()` from `__tests__/mock-require.js` to load its
+modules and install mock exports via `mockRequire()`. The fixture isolates
+the Function's CommonJS cache and restores it after each suite.
+
 The tests in `__tests__/index.test.js` exercise the webhook handler
 end-to-end with heavily mocked dependencies. When adding `/deploy`-style
 tests, keep these harness facts in mind:
 
-- `afterEach` calls `jest.clearAllMocks()` and empties `dispatchedWorkflows`,
+- `afterEach` calls `vi.clearAllMocks()` and empties `dispatchedWorkflows`,
   so `toHaveBeenCalledTimes(...)` counts are per-test.
 - The GitHub API is mocked in `mockGitHubApiRequest`. Looking up a PR's
   head SHA goes through `GET .../pulls/<number>`, so **each PR number used
@@ -232,9 +230,9 @@ one-time setup.
 
 ## Validating Changes
 
-1. **Lint and test**: `npm run lint` and `npx jest __tests__/`.
+1. **Lint and test**: `npm run lint` and `npm test`.
 2. **Dispatch contracts**: if you change a dispatched workflow filename or
    a queued check-run name/summary, update `git-for-windows-automation`
    (and re-check its `AGENTS.md`) in lockstep.
-3. **Leave `embargoed-builds/` alone** unless you are deliberately working
-   on that branch.
+3. **Leave nested worktrees alone** unless you are deliberately working
+   on their branch.

__tests__/component-updates.test.js

@@ -1,3 +1,7 @@
+import { expect, test, vi } from 'vitest'
+import { createMockRequire } from './mock-require.js'
+
+const { require, mockRequire } = createMockRequire()
 const {
     guessComponentUpdateDetails,
     guessReleaseNotes,
@@ -55,13 +59,11 @@ test('guessComponentUpdateDetails()', () => {
     )).toEqual({ package_name: 'pcre2', version: '10.49' })
 })
 
-let mockGithubApiRequest = jest.fn(() => {
+let mockGithubApiRequest = vi.fn(() => {
     return {
     }
 })
-jest.mock('../GitForWindowsHelper/github-api-request', () => {
-    return mockGithubApiRequest
-})
+mockRequire('../GitForWindowsHelper/github-api-request', mockGithubApiRequest)
 
 const mockFetchHTML = {
     'https://cygwin.com': `<div>
@@ -95,7 +97,7 @@ const bogus32BitMSYS2RuntimeURL = 'https://raw.githubusercontent.com/git-for-win
 const bogus64BitMSYS2RuntimeURL = 'https://raw.githubusercontent.com/git-for-windows/pacman-repo/refs/heads/x86_64/msys2-runtime-3.3-3.3.7-1-x86_64.pkg.tar.xz'
 const missingOpenSSHURL = 'https://raw.githubusercontent.com/git-for-windows/pacman-repo/refs/heads/i686/openssh-9.5p1-1-i686.pkg.tar.xz'
 const missingBashURL = 'https://raw.githubusercontent.com/git-for-windows/pacman-repo/refs/heads/x86_64/bash-5.2.020-1-x86_64.pkg.tar.xz'
-const mockDoesURLReturn404 = jest.fn(url => [
+const mockDoesURLReturn404 = vi.fn(url => [
     missingURL,
     missingAarch64URL,
     missingMinTTYURL,
@@ -104,16 +106,14 @@ const mockDoesURLReturn404 = jest.fn(url => [
     missingOpenSSHURL,
     missingBashURL
 ].includes(url))
-jest.mock('../GitForWindowsHelper/https-request', () => {
-    return {
-        doesURLReturn404: mockDoesURLReturn404,
-        fetchHTML: jest.fn(url => mockFetchHTML[url])
-    }
+mockRequire('../GitForWindowsHelper/https-request', {
+    doesURLReturn404: mockDoesURLReturn404,
+    fetchHTML: vi.fn(url => mockFetchHTML[url])
 })
 
 
 test('guessReleaseNotes()', async () => {
-    const context = { log: jest.fn() }
+    const context = { log: vi.fn() }
     expect(await guessReleaseNotes(context, {
         labels: [{ name: 'component-update' }],
         title: '[New bash version] 3 new items',

__tests__/index.test.js

@@ -1,11 +1,15 @@
+import { afterEach, expect, test, vi } from 'vitest'
+import { createMockRequire } from './mock-require.js'
+
+const { require, mockRequire } = createMockRequire()
 const index = require('../GitForWindowsHelper/index')
 const crypto = require('crypto')
 
 process.env['GITHUB_WEBHOOK_SECRET'] = 'for-testing'
 
 test('reject requests other than webhook payloads', async () => {
     const context = {
-        log: jest.fn(),
+        log: vi.fn(),
         req: {
             method: 'GET'
         }
@@ -26,7 +30,7 @@ test('reject requests other than webhook payloads', async () => {
 
     await expectInvalidWebhook('Unexpected method: GET')
 
-    context.log = jest.fn()
+    context.log = vi.fn()
     context.req.method = 'POST'
     context.req.headers = {
         'content-type': 'text/plain'
@@ -44,18 +48,22 @@ test('reject requests other than webhook payloads', async () => {
     await expectInvalidWebhook('Incorrect X-Hub-Signature')
 })
 
-let mockGetInstallationAccessToken = jest.fn(() => 'installation-access-token')
-jest.mock('../GitForWindowsHelper/get-installation-access-token', () => {
-    return mockGetInstallationAccessToken
-})
+let mockGetInstallationAccessToken = vi.fn(() => 'installation-access-token')
+mockRequire(
+    '../GitForWindowsHelper/get-installation-access-token',
+    mockGetInstallationAccessToken
+)
 
-let mockGitHubApiRequestAsApp = jest.fn()
-jest.mock('../GitForWindowsHelper/github-api-request-as-app', () => {
-    return mockGitHubApiRequestAsApp
-})
+let mockGitHubApiRequestAsApp = vi.fn()
+mockRequire(
+    '../GitForWindowsHelper/github-api-request-as-app',
+    mockGitHubApiRequestAsApp
+)
 
 const dispatchedWorkflows = []
-let mockGitHubApiRequest = jest.fn((_context, _token, method, requestPath, payload) => {
+let mockGitHubApiRequest = vi.fn((
+    _context, _token, method, requestPath, payload
+) => {
     if (method === 'POST' && requestPath.endsWith('/comments')) return {
         id: -124,
         html_url: `new-comment-url-${payload.body}`
@@ -207,12 +215,10 @@ The \`git-artifacts-mingw64\` workflow run [was started](dispatched-workflow-git
     }
     throw new Error(`Unhandled ${method}-${requestPath}-${JSON.stringify(payload)}`)
 })
-jest.mock('../GitForWindowsHelper/github-api-request', () => {
-    return mockGitHubApiRequest
-})
+mockRequire('../GitForWindowsHelper/github-api-request', mockGitHubApiRequest)
 
 afterEach(() => {
-    jest.clearAllMocks()
+    vi.clearAllMocks()
     dispatchedWorkflows.splice(0, dispatchedWorkflows.length) // empty the array
 })
 
@@ -229,7 +235,7 @@ const makeContext = (body, headers) => {
     const rawBody = JSON.stringify(body)
     const sha256 = crypto.createHmac('sha256', process.env['GITHUB_WEBHOOK_SECRET']).update(rawBody).digest('hex')
     return {
-        log: jest.fn(),
+        log: vi.fn(),
         req: {
             body,
             headers: {
@@ -321,12 +327,13 @@ testIssueComment('/hi', async (context) => {
     ])
 })
 
-let mockGetInstallationIDForRepo = jest.fn(() => 'installation-id')
-jest.mock('../GitForWindowsHelper/get-installation-id-for-repo', () => {
-    return mockGetInstallationIDForRepo
-})
+let mockGetInstallationIDForRepo = vi.fn(() => 'installation-id')
+mockRequire(
+    '../GitForWindowsHelper/get-installation-id-for-repo',
+    mockGetInstallationIDForRepo
+)
 
-let mockSearchIssues = jest.fn((_context, searchTerms) => {
+let mockSearchIssues = vi.fn((_context, searchTerms) => {
     if (searchTerms.indexOf('release-git') > 0) return [{
         number: 765,
         author_association: 'MEMBER',
@@ -336,10 +343,8 @@ let mockSearchIssues = jest.fn((_context, searchTerms) => {
     }]
     return []
 })
-jest.mock('../GitForWindowsHelper/search', () => {
-    return {
-        searchIssues: mockSearchIssues
-    }
+mockRequire('../GitForWindowsHelper/search', {
+    searchIssues: mockSearchIssues
 })
 
 testIssueComment('/open pr', {
@@ -544,9 +549,11 @@ The workflow run [was started](dispatched-workflow-updpkgsums.yml).`
     })
 })
 
-let mockQueueCheckRun = jest.fn(() => 'check-run-id')
-let mockUpdateCheckRun = jest.fn()
-let mockListCheckRunsForCommit = jest.fn((_context, _token, _owner, _repo, rev, checkRunName) => {
+let mockQueueCheckRun = vi.fn(() => 'check-run-id')
+let mockUpdateCheckRun = vi.fn()
+let mockListCheckRunsForCommit = vi.fn((
+    _context, _token, _owner, _repo, rev, checkRunName
+) => {
     const app = {
         slug: 'gitforwindowshelper'
     }
@@ -627,12 +634,10 @@ let mockListCheckRunsForCommit = jest.fn((_context, _token, _owner, _repo, rev,
     }]
     return []
 })
-jest.mock('../GitForWindowsHelper/check-runs', () => {
-    return {
-        queueCheckRun: mockQueueCheckRun,
-        updateCheckRun: mockUpdateCheckRun,
-        listCheckRunsForCommit: mockListCheckRunsForCommit
-    }
+mockRequire('../GitForWindowsHelper/check-runs', {
+    queueCheckRun: mockQueueCheckRun,
+    updateCheckRun: mockUpdateCheckRun,
+    listCheckRunsForCommit: mockListCheckRunsForCommit
 })
 
 testIssueComment('/deploy', {
@@ -866,10 +871,11 @@ The workflow run [was started](dispatched-workflow-build-and-deploy.yml).`)
 })
 
 const missingURL = 'https://raw.githubusercontent.com/git-for-windows/pacman-repo/refs/heads/x86_64/mingw-w64-x86_64-git-lfs-3.4.0-1-any.pkg.tar.xz'
-const mockDoesURLReturn404 = jest.fn(url => url === missingURL)
-const mockFetchHTML = jest.fn(() => 'pkgver=10.48\n')
-jest.mock('../GitForWindowsHelper/https-request', () => {
-    return { doesURLReturn404: mockDoesURLReturn404, fetchHTML: mockFetchHTML }
+const mockDoesURLReturn404 = vi.fn(url => url === missingURL)
+const mockFetchHTML = vi.fn(() => 'pkgver=10.48\n')
+mockRequire('../GitForWindowsHelper/https-request', {
+    doesURLReturn404: mockDoesURLReturn404,
+    fetchHTML: mockFetchHTML
 })
 
 testIssueComment('/add release note', {
@@ -1016,7 +1022,7 @@ The \`tag-git\` workflow run [was started](dispatched-workflow-tag-git.yml)`,
         snapshot: 'false'
     })
 
-    jest.clearAllMocks()
+    vi.clearAllMocks()
     dispatchedWorkflows.splice(0, dispatchedWorkflows.length) // empty the array
 
     // with existing `tag-git` run

__tests__/mock-require.js

@@ -0,0 +1,30 @@
+import { afterAll } from 'vitest'
+import { createRequire } from 'node:module'
+import { fileURLToPath } from 'node:url'
+
+export const createMockRequire = () => {
+    const require = createRequire(import.meta.url)
+    const directory = fileURLToPath(
+        new URL('../GitForWindowsHelper/', import.meta.url)
+    )
+    const originals = new Map()
+    for (const [id, module] of Object.entries(require.cache)) {
+        if (id.startsWith(directory)) {
+            originals.set(id, module)
+            delete require.cache[id]
+        }
+    }
+
+    afterAll(() => {
+        for (const id of Object.keys(require.cache)) {
+            if (id.startsWith(directory)) delete require.cache[id]
+        }
+        for (const [id, module] of originals) require.cache[id] = module
+    })
+
+    const mockRequire = (path, exports) => {
+        const id = require.resolve(path)
+        require.cache[id] = { exports, loaded: true }
+    }
+    return { require, mockRequire }
+}

eslint.config.js

@@ -1,20 +1,15 @@
 const js = require("@eslint/js")
-const jest = require("eslint-plugin-jest")
 const globals = require("globals")
 
 module.exports = [
     js.configs.recommended,
     {
-        plugins: {
-            jest: jest
-        },
         languageOptions: {
             ecmaVersion: 12,
             sourceType: "module",
             globals: {
                 ...globals.node,
-                ...globals.es6,
-                ...globals.jest
+                ...globals.es6
             }
         },
         rules: {