Implement AutomationNode.querySelector().

chrome/test/data/extensions/api_test/automation/tests/tabs/query.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 = [
-  function testSimpleAction() {
+  function testQuery() {
     var okButton = rootNode.firstChild().firstChild();
-    okButton.addEventListener(EventType.focus, function() {
+    function assertCorrectResult(queryResult) {
+      console.log(okButton.toString());
+      console.log(queryResult.toString());
+      assertEq(queryResult, okButton);
       chrome.test.succeed();
-    }, true);
-    okButton.focus();
+    }
+
+    rootNode.query({'selector': 'button'}, assertCorrectResult);

[dmazzoni, 2014/10/27 18:57:08]

Please add a test that does some crazy CSS selector just to demonstrate that
it's giving you the full power of CSS here - like foo not(#bar) >
.baz:nth_child(2) or something like that

[aboxhall, 2014/10/28 23:43:57]

Yeah, this is actually a terrible example anyway since you'd almost never
execute querySelector('button') anyway, even in regular DOM (you'd probably
either want all the buttons, or a specific button that you'd select by ID or
class or something)

   }
 ];
 
 setUpAndRunTests(allTests);