test: add a test for page.close w/ dialogs

test/page-close.spec.ts

@@ -0,0 +1,28 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications 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 { it } from './fixtures';
+
+it('should close page with active dialog', (test, { browserName, platform }) => {
+  test.fixme(browserName === 'webkit' && platform === 'darwin', 'WebKit hangs on a Mac');
+}, async ({context}) => {
+  const page = await context.newPage();
+  await page.setContent(`<button onclick="setTimeout(() => alert(1))">alert</button>`);
+  page.click('button');
+  await page.waitForEvent('dialog');
+  await page.close();
+});