Implement AutomationNode.querySelector().

chrome/test/data/extensions/api_test/automation/tests/tabs/queryselector.js

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+var allTests = [
+  // Basic query from root node.
+  function testQuerySelector() {
+    var cancelButton = rootNode.lastChild().lastChild();
+    function assertCorrectResult(queryResult) {
+      assertEq(queryResult, cancelButton);
+      chrome.test.succeed();
+    }
+    rootNode.querySelector('body > button:nth-of-type(2)',
+                           assertCorrectResult);
+  },
+
+  function testQuerySelectorNoMatch() {
+    function assertCorrectResult(queryResult) {
+      assertEq(queryResult, null);
+      chrome.test.succeed();
+    }
+    rootNode.querySelector('#nonexistent',
+                           assertCorrectResult);
+  },
+
+  // Demonstrates that a query from a non-root element queries inside that
+  // element.
+  function testQuerySelectorFromMain() {
+    var main = rootNode.children()[1];
+    console.log('main: ' + main.toString());

[Devlin, 2014/10/31 22:11:28]

reminder: Remove these logs.

[aboxhall, 2014/10/31 23:06:48]

Done.

+    // paragraph inside "main" element - not the first <p> on the page
+    var p = main.firstChild();
+    function assertCorrectResult(queryResult) {
+      assertEq(queryResult, p);
+      chrome.test.succeed();
+    }
+    main.querySelector('p', assertCorrectResult);
+  },
+
+  // Demonstrates that a query for an element which is ignored for accessibility
+  // returns its nearest ancestor.
+  function testQuerySelectorForSpanInsideButtonReturnsButton() {
+    var okButton = rootNode.lastChild().firstChild();
+    function assertCorrectResult(queryResult) {
+      assertEq(queryResult, okButton);
+      chrome.test.succeed();
+    }
+    rootNode.querySelector('#span-in-button', assertCorrectResult);
+  },
+
+  // Demonstrates that querying from an anonymous node may have unexpected
+  // results.
+  function testQuerySelectorFromAnonymousGroup() {
+    var h1 = rootNode.firstChild().firstChild();
+    var group = rootNode.lastChild();
+    function assertCorrectResult(queryResult) {
+      assertEq(h1, queryResult);
+      chrome.test.succeed();
+    }
+    group.querySelector('h1', assertCorrectResult);
+  },
+
+  function testQuerySelectorFromRemovedNode() {
+    var group = rootNode.firstChild();
+    function assertCorrectResult(queryResult) {
+      assertEq(null, queryResult);
+      var errorMsg =
+          'querySelector sent on node which is no longer in the tree';
+      assertEq(errorMsg, chrome.extension.lastError.message);
+      assertEq(errorMsg, chrome.runtime.lastError.message);
+
+      chrome.test.succeed();
+    }
+    function afterRemoveChild() {
+      group.querySelector('h1', assertCorrectResult);
+    }
+    chrome.tabs.executeScript(
+        { code: 'document.body.removeChild(document.body.firstElementChild)' },
+        afterRemoveChild);
+  }
+];
+
+setUpAndRunTests(allTests, 'complex.html');