chore(ci): add workflow for windows smoke tests

.github/workflows/windows.yml

@@ -0,0 +1,64 @@
+name: Smoke Test Windows
+
+on:
+    push:
+        branches:
+            - master
+            - release
+            - 'spring*'
+            - 'summer*'
+            - 'winter*'
+    pull_request:
+
+env:
+    COVERAGE: '1'
+
+jobs:
+    smoke-test-windows:
+        runs-on: windows-2025
+        steps:
+            - name: Checkout repository
+              uses: actions/checkout@v5
+
+            - name: Setup Node
+              uses: actions/setup-node@v6
+              with:
+                  node-version: '20.19.4'
+                  cache: 'yarn'
+
+            - name: Install dependencies
+              run: yarn install --frozen-lockfile
+
+            - name: Run unit tests
+              run: yarn test run
+
+            - name: Get installed playwright version
+              id: playwright-version
+              run: |
+                  version="$(yarn --silent --json list --depth 0 playwright 2>/dev/null | jq -r '.data.trees[0].name|split("@")[1]')"
+                  echo "version=$version" >> "$GITHUB_OUTPUT"
+
+            - name: Restore playwright cache
+              uses: actions/cache@v4
+              id: playwright-cache
+              with:
+                  path: ~\AppData\Local\ms-playwright
+                  key: ${{ runner.os }}-playwright-${{ steps.playwright-version.outputs.version }}
+
+            - name: Install playwright dependencies
+              id: install-playwright
+              continue-on-error: true
+              run: yarn playwright install chromium --with-deps
+              timeout-minutes: 3 # Sometimes seems to just hang forever? :|
+
+            # If installing playwright times out, wait 1 minute then try again
+            - name: Install playwright dependencies
+              if: ${{ steps.install-playwright.outcome != 'success' }}
+              run: sleep 60 && yarn playwright install chromium --with-deps
+              timeout-minutes: 4
+
+            - name: Run integration tests
+              run: yarn test || yarn test
+              env:
+                  BROWSERS: chromium
+              working-directory: packages/@lwc/integration-not-karma

packages/@lwc/engine-server/src/__tests__/fixtures.spec.ts

@@ -70,7 +70,7 @@ async function compileFixture({
             .join('-') || 'default';
     const modulesDir = path.resolve(dirname, './modules');
     const outputFile = path.resolve(dirname, `./dist/compiled-${optionsAsString}.js`);
-    const input = 'virtual/fixture/test.js';
+    const input = path.normalize('virtual/fixture/test.js');
 
     const bundle = await rollup({
         input,

packages/@lwc/integration-not-karma/README.md

@@ -24,6 +24,8 @@ Environment variables are used as controls to run tests in different modes (e.g
 
 By default, the tests are run using Playwright. If the `USE_SAUCE` env var is set, then SauceLabs is used instead. To use SauceLabs, the `SAUCE_USERNAME`, `SAUCE_ACCESS_KEY`, and `SAUCE_TUNNEL_ID` env vars must be set.
 
+To run tests in a specific browser, rather than the defaults specified, set the `BROWSERS` env var.
+
 ### Integration Tests
 
 Integration tests are simply `.spec.js` files that run in the browser. LWC components are transformed by a plugin defined in `serve-integration.js`.

packages/@lwc/integration-not-karma/configs/shared/browsers.js

@@ -45,10 +45,7 @@ export function getBrowsers(options) {
                   }),
               ];
     } else {
-        return [
-            playwrightLauncher({ product: 'chromium' }),
-            playwrightLauncher({ product: 'firefox' }),
-            playwrightLauncher({ product: 'webkit' }),
-        ];
+        const browsers = options.BROWSERS?.split(',') ?? ['chromium', 'firefox', 'webkit'];
+        return browsers.map((product) => playwrightLauncher({ product }));
     }
 }

packages/@lwc/integration-not-karma/helpers/options.js

@@ -6,9 +6,6 @@ import { HIGHEST_API_VERSION } from '@lwc/shared';
 
 // --- Boolean test flags --- //
 
-/** Run SauceLabs tests using only "legacy" browsers. */
-export const LEGACY_BROWSERS = Boolean(process.env.LEGACY_BROWSERS);
-
 /** Force tests to run in native shadow mode with synthetic shadow polyfill patches. */
 export const FORCE_NATIVE_SHADOW_MODE_FOR_TEST = Boolean(
     process.env.FORCE_NATIVE_SHADOW_MODE_FOR_TEST
@@ -58,28 +55,16 @@ export const API_VERSION = process.env.API_VERSION
 /** The `NODE_ENV` to set for tests (at runtime, in the browser). */
 export const NODE_ENV_FOR_TEST = process.env.NODE_ENV_FOR_TEST || 'development';
 
-/** Unique directory name that encodes the flags that the tests were executed with. */
-export const COVERAGE_DIR_FOR_OPTIONS =
-    Object.entries({
-        API_VERSION,
-        DISABLE_STATIC_CONTENT_OPTIMIZATION,
-        SHADOW_MODE_OVERRIDE,
-        DISABLE_SYNTHETIC_SHADOW_SUPPORT_IN_COMPILER,
-        ENABLE_ARIA_REFLECTION_GLOBAL_POLYFILL,
-        FORCE_NATIVE_SHADOW_MODE_FOR_TEST,
-        LEGACY_BROWSERS,
-        NODE_ENV_FOR_TEST,
-        DISABLE_NATIVE_CUSTOM_ELEMENT_LIFECYCLE,
-        ENGINE_SERVER,
-        DISABLE_DETACHED_REHYDRATION,
-    })
-        .filter(([, val]) => val)
-        .map(([key, val]) => `${key}=${val}`)
-        .join('/') || 'no-options';
+/**
+ * Comma-delimited list of browser names to run with Playwright.
+ * Possible values are `chromium`, `firefox`, and `webkit`.
+ * Ignored if the `USE_SAUCE` env var is set.
+ */
+export const BROWSERS = process.env.BROWSERS;
 
 // --- CI config --- //
 
-/** Whether or not to report coverage. Currently unused. */
+/** Whether or not to report coverage. */
 export const COVERAGE = Boolean(process.env.COVERAGE);
 /** Whether or not we're running in CI. */
 export const CI = Boolean(process.env.CI);
@@ -102,3 +87,5 @@ export const {
     /** SauceLabs tunnel ID. */
     SAUCE_TUNNEL_ID,
 } = process.env;
+/** Run SauceLabs tests using only "legacy" browsers. */
+export const LEGACY_BROWSERS = Boolean(process.env.LEGACY_BROWSERS);

packages/@lwc/ssr-compiler/src/__tests__/fixtures.spec.ts

@@ -65,7 +65,7 @@ async function compileFixture({
 }) {
     const modulesDir = path.resolve(dirname, './modules');
     const outputFile = path.resolve(dirname, './dist/compiled-experimental-ssr.js');
-    const input = 'virtual/fixture/test.js';
+    const input = path.normalize('virtual/fixture/test.js');
 
     const bundle = await rollup({
         input,