drive: Make FileManagerBrowserTest more robust

chrome/test/data/extensions/api_test/file_manager_browsertest/background.js

 // Copyright (c) 2013 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.
 
 // These must match the files created in the C++ code.
 var EXPECTED_FILES_BEFORE = [
   ['hello.txt', '123 bytes', 'Plain text', 'Sep 4, 1998 12:34 PM'],
   ['world.mpeg', '1,000 bytes', 'MPEG video', 'Jul 4, 2012 10:35 AM'],
   ['My Desktop Background.png', '1 KB', 'PNG image', 'Jan 18, 2038 1:02 AM'],
   ['photos', '--', 'Folder', 'Jan 1, 1980 11:59 PM']
@@ skipping 66 matching lines @@
       else
         window.setTimeout(helper, 50);
     });
   }
   helper();
 }
 
 // Checks that the files initially added by the C++ side are displayed, and
 // that a subsequently added file shows up.
 function testFileDisplay() {
-  getFileList(function(actualFilesBefore) {
-    chrome.test.assertEq(EXPECTED_FILES_BEFORE, actualFilesBefore);
-    chrome.test.sendMessage('initial check done', function(reply) {
-      chrome.test.assertEq('file added', reply);
-      waitForFileListChange(
+  waitForFileListChange(
+    0,
+    function(actualFilesBefore) {
+      chrome.test.assertEq(EXPECTED_FILES_BEFORE, actualFilesBefore);
+      chrome.test.sendMessage('initial check done', function(reply) {
+        chrome.test.assertEq('file added', reply);
+        waitForFileListChange(
           EXPECTED_FILES_BEFORE.length,
           chrome.test.callbackPass(function(actualFilesAfter) {
             chrome.test.assertEq(EXPECTED_FILES_AFTER, actualFilesAfter);
           }));
+      });
     });
-  });
 }
 
 // Injects the keyboard test code into the file manager tab and runs the
 // keyboard delete test.
 function doKeyboardTestWithConfirmation(code) {
   chrome.tabs.executeScript(null, {file: 'fake_keypress.js'}, function(result) {

[satorux1, 2013/04/05 08:15:11]

fixed here too

     chrome.tabs.executeScript(null, {code: code}, function(result) {
       chrome.test.assertFalse(!result[0]);
       waitAndAcceptDialog(function() {
         // Succeed here if anything happens; the C++ code checks what happened.
         waitForFileListChange(EXPECTED_FILES_BEFORE.length,
                               chrome.test.succeed);
       });
     });
   });
 }
 
 // Injects the keyboard test code into the file manager tab and runs the
 // keyboard copy test.
 function doKeyboardTest(code) {

[mtomasz, 2013/04/05 07:59:44]

I think this can also be flaky.

It can pass if copying doesn't work. A change in file list is interpreted as a
successful copy, while it could be just the file list initialized.

Shall we wrap it with waitForFileListChange(0, ...) to wait util the file list
is rendered?

[mtomasz, 2013/04/05 08:10:49]

Actually it can even pass if the list is not yet initialized!

[satorux1, 2013/04/05 08:15:11]

Good idea! Done.

   chrome.tabs.executeScript(null, {file: 'fake_keypress.js'}, function(result) {
     chrome.tabs.executeScript(null, {code: code}, function(result) {
       chrome.test.assertFalse(!result[0]);
       // Succeed here if anything happens; the C++ code checks what happened.
       waitForFileListChange(EXPECTED_FILES_BEFORE.length, chrome.test.succeed);
     });
   });
 }
 
 chrome.test.runTests([
   // Waits for the C++ code to send a string identifying a test, then runs that
   // test.
   function testRunner() {
     chrome.test.sendMessage('which test', function(reply) {
       // These test names are provided by file_manager_browsertest.cc.
       if (reply === 'file display') {
         testFileDisplay();
       } else if (reply === 'keyboard copy') {
         doKeyboardTest('fakeFileCopy("world.mpeg");');
       } else if (reply === 'keyboard delete') {
         doKeyboardTestWithConfirmation('fakeFileDelete("world.mpeg");');
       } else {
         chrome.test.fail('Bogus test name passed to testRunner()');
       }
     });
   }
 ]);