feat: enable parallel Playwright e2e test execution (#2547)

.github/workflows/ci.yml

@@ -290,6 +290,8 @@ jobs:
       - name: E2E tests (Shard ${{ matrix.shard }}/${{ matrix.shardTotal }})
         env:
           FLAKINESS_ACCESS_TOKEN: ${{ secrets.FLAKINESS_ACCESS_TOKEN }}
+          # Self-hosted macOS runners can handle more parallelism
+          PLAYWRIGHT_PARALLELISM: ${{ contains(matrix.os.image, 'self-hosted') && '3' || '1' }}
         # You can add debug logging to make it easier to see what's failing
         # by adding "DEBUG=pw:browser" in front.
         # Use blob reporter for sharding and merge capabilities

playwright.config.ts

@@ -5,7 +5,9 @@ const timestamp = new Date().toISOString().replace(/[:.]/g, "-");
 
 const config: PlaywrightTestConfig = {
   testDir: "./e2e-tests",
-  workers: 1,
+  // Enable parallel test execution - E2E test builds skip the singleton lock
+  // Read parallelism from env var, default to 1 if not set
+  workers: parseInt(process.env.PLAYWRIGHT_PARALLELISM || "1", 10),
   retries: process.env.CI ? 2 : 0,
   timeout: process.env.CI ? 180_000 : 75_000,
   // Use a custom snapshot path template because Playwright's default

src/main.ts

@@ -380,21 +380,31 @@ const createApplicationMenu = () => {
   Menu.setApplicationMenu(appMenu);
 };
 
-const gotTheLock = app.requestSingleInstanceLock();
-
-if (!gotTheLock) {
-  app.quit();
-} else {
-  app.on("second-instance", (_event, commandLine, _workingDirectory) => {
-    // Someone tried to run a second instance, we should focus our window.
-    if (mainWindow) {
-      if (mainWindow.isMinimized()) mainWindow.restore();
-      mainWindow.focus();
-    }
-    // the commandLine is array of strings in which last element is deep link url
-    handleDeepLinkReturn(commandLine.pop()!);
-  });
+// Skip singleton lock for E2E test builds to allow parallel test execution.
+// Deep link handling still works via the 'open-url' event registered below.
+// The 'second-instance' handler is intentionally omitted since it requires the singleton lock.
+if (IS_TEST_BUILD) {
   app.whenReady().then(onReady);
+} else {
+  const gotTheLock = app.requestSingleInstanceLock();
+
+  if (!gotTheLock) {
+    app.quit();
+  } else {
+    app.on("second-instance", (_event, commandLine, _workingDirectory) => {
+      // Someone tried to run a second instance, we should focus our window.
+      if (mainWindow) {
+        if (mainWindow.isMinimized()) mainWindow.restore();
+        mainWindow.focus();
+      }
+      // the commandLine is array of strings in which last element is deep link url
+      const url = commandLine.at(-1);
+      if (url) {
+        handleDeepLinkReturn(url);
+      }
+    });
+    app.whenReady().then(onReady);
+  }
 }
 
 // Handle the protocol. In this case, we choose to show an Error Box.