chore: allow reusing browser between the tests (#22191)

packages/playwright-core/src/remote/playwrightConnection.ts

@@ -282,4 +282,5 @@ const defaultLaunchOptions: LaunchOptions = {
 
 const optionsThatAllowBrowserReuse: (keyof LaunchOptions)[] = [
   'headless',
+  'tracesDir',
 ];

tests/playwright-test/playwright.reuse.browser.spec.ts

@@ -0,0 +1,63 @@
+/**
+ * Copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { test as baseTest, expect } from './playwright-test-fixtures';
+import { RunServer } from '../config/remoteServer';
+import type { PlaywrightServer } from '../config/remoteServer';
+
+const test = baseTest.extend<{ runServer: () => Promise<PlaywrightServer> }>({
+  runServer: async ({ childProcess }, use) => {
+    let server: PlaywrightServer | undefined;
+    await use(async () => {
+      const runServer = new RunServer();
+      await runServer._start(childProcess);
+      server = runServer;
+      return server;
+    });
+    if (server) {
+      await server.close();
+      // Give any connected browsers a chance to disconnect to avoid
+      // poisoning next test with quasy-alive browsers.
+      await new Promise(f => setTimeout(f, 1000));
+    }
+  },
+});
+
+test('should reuse browser', async ({ runInlineTest, runServer }) => {
+  const server = await runServer();
+  const result = await runInlineTest({
+    'src/a.test.ts': `
+      import { test, expect } from '@playwright/test';
+      test('a', async ({ browser }) => {
+        console.log('%%' + process.env.TEST_WORKER_INDEX + ':' + browser._guid);
+      });
+    `,
+    'src/b.test.ts': `
+      import { test, expect } from '@playwright/test';
+      test('b', async ({ browser }) => {
+        console.log('%%' + process.env.TEST_WORKER_INDEX + ':' + browser._guid);
+      });
+    `,
+  }, { workers: 2 }, { PW_TEST_REUSE_CONTEXT: '1', PW_TEST_CONNECT_WS_ENDPOINT: server.wsEndpoint() });
+
+  expect(result.exitCode).toBe(0);
+  expect(result.passed).toBe(2);
+  expect(result.outputLines).toHaveLength(2);
+  const [workerIndex1, guid1] = result.outputLines[0].split(':');
+  const [workerIndex2, guid2] = result.outputLines[1].split(':');
+  expect(guid2).toBe(guid1);
+  expect(workerIndex2).not.toBe(workerIndex1);
+});