Add a script to test Chrome with the NVDA screen reader.

tools/accessibility/nvda/nvda_chrome_tests.py

+#!/usr/bin/env python
+# Copyright (c) 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.
+
+"""Semi-automated tests of Chrome with NVDA.

[David Tseng, 2014/06/30 16:55:28]

What does it mean to be semi automated?

[dmazzoni, 2014/07/15 06:09:58]

Clarified in comments. I basically mean that it's not really set up to run on a
build bot, you have to manually kick off the tests, but they're automated
otherwise.

+
+This file performs Semi-automated tests of Chrome with NVDA
+(NonVisual Desktop Access), a popular open-source screen reader for
+visually impaired users on Windows. It works by launching Chrome in a
+subprocess, then launching NVDA in a special environment that simulates
+speech rather than actually speaking, and ignores all events coming from
+processes other than a specific Chrome process ID. Each test automates
+Chrome with a series of actions and asserts that NVDA gives the expected
+feedback in response."""
+
+import os
+import pywinauto
+import re
+import shutil
+import subprocess
+import sys
+import tempfile
+import time
+import unittest
+
+CHROME_PROFILES_PATH = os.path.join(os.getcwd(), 'chrome_profiles')
+CHROME_PATH = os.path.join(os.environ['USERPROFILE'],
+                           'AppData',
+                           'Local',
+                           'Google',
+                           'Chrome SxS',
+                           'Application',
+                           'chrome.exe')
+NVDA_PATH = os.path.join(os.getcwd(),
+                         'nvdaPortable',
+                         'nvda_noUIAccess.exe')
+NVDA_PROCTEST_PATH = os.path.join(os.getcwd(),
+                                  'nvda-proctest')
+NVDA_LOGPATH = os.path.join(os.getcwd(),
+                            'nvda_log.txt')
+
+class NvdaChromeTest(unittest.TestCase):
+  @classmethod
+  def setUpClass(cls):
+    print 'user data: %s' % CHROME_PROFILES_PATH
+    print 'chrome: %s' % CHROME_PATH
+    print 'nvda: %s' % NVDA_PATH
+    print 'nvda_proctest: %s' % NVDA_PROCTEST_PATH
+
+    print
+    print 'Clearing user data directory and log file from previous runs'
+    if os.access(CHROME_PROFILES_PATH, os.F_OK):
+      shutil.rmtree(CHROME_PROFILES_PATH)
+    if os.access(NVDA_LOGPATH, os.F_OK):
+      os.remove(NVDA_LOGPATH)
+    os.mkdir(CHROME_PROFILES_PATH, 0777)
+
+  def setUp(self):
+    user_data_dir = tempfile.mkdtemp(dir = CHROME_PROFILES_PATH)
+    args = [CHROME_PATH,
+            '--user-data-dir=%s' % user_data_dir,
+            '--no-first-run',
+            'about:blank']
+    print
+    print ' '.join(args)
+    self._chrome_proc = subprocess.Popen(args)
+    self._chrome_proc.poll()
+    if self._chrome_proc.returncode is None:
+      print 'Chrome is running'
+    else:
+      print 'Chrome exited with code', self._chrome_proc.returncode
+      sys.exit()
+    print 'Chrome pid: %d' % self._chrome_proc.pid
+    time.sleep(1)

[David Tseng, 2014/06/30 16:55:28]

Is this needed? Looks flakey.

[dmazzoni, 2014/07/15 06:09:58]

OK, I successfully removed this and replaced it with a WaitForSpeech helper
function.

+
+    os.environ['NVDA_SPECIFIC_PROCESS'] = str(self._chrome_proc.pid)
+
+    args = [NVDA_PATH,
+            '-m',
+            '-c',
+            NVDA_PROCTEST_PATH,
+            '-f',
+            NVDA_LOGPATH]
+    self._nvda_proc = subprocess.Popen(args)
+    self._nvda_proc.poll()
+    if self._nvda_proc.returncode is None:
+      print 'NVDA is running'
+    else:
+      print 'NVDA exited with code', self._nvda_proc.returncode
+      sys.exit()
+    print 'NVDA pid: %d' % self._nvda_proc.pid
+    time.sleep(1)

[David Tseng, 2014/06/30 16:55:28]

Ditto.

+

[David Tseng, 2014/06/30 16:55:29]

Wrt ordering, do we ever want to test Chrome initial launch with NVDA already
enabled?

[dmazzoni, 2014/07/15 06:09:58]

Sure. My guess is that opening a new browser window would cover 90% of the
possible issues with opening Chrome from scratch so I'll probably start there.

[dmazzoni, 2014/07/15 15:41:18]

Oh, I almost forgot - one big reason I did it in this order is because NVDA gave
us a command-line argument that tells it to pay attention to just one process id
and ignore any others. That helps cut down on flakiness a lot, because otherwise
it would announce any notifications or events from other applications. if we
started NVDA and then Chrome, the test has the potential to be a bit flakier.

+    app = pywinauto.application.Application()
+    app.connect_(process = self._chrome_proc.pid)
+    self._pywinauto_window = app.top_window_()
+
+  def tearDown(self):
+    print
+    print 'Shutting down'
+
+    self._chrome_proc.poll()
+    if self._chrome_proc.returncode is None:
+      print 'Killing Chrome subprocess'
+      self._chrome_proc.kill()
+    else:
+      print 'Chrome already died.'
+
+    self._nvda_proc.poll()
+    if self._nvda_proc.returncode is None:
+      print 'Killing Nvda subprocess'

[David Tseng, 2014/06/30 16:55:29]

nit: NVDA

[dmazzoni, 2014/07/15 06:09:58]

Done.

+      self._nvda_proc.kill()
+    else:
+      print 'Nvda already died.'

[David Tseng, 2014/06/30 16:55:29]

Ditto.

[dmazzoni, 2014/07/15 06:09:58]

Done.

+
+  def _GetSpeechFromNvdaLogFile(self):
+    """Return everything NVDA would have spoken as a list of strings.
+
+    Parses lines like this from NVDA's log file:
+      Speaking [LangChangeCommand ('en'), u'Google Chrome', u'window']
+      Speaking character u'slash'
+
+    Returns a single list of strings like this:
+      [u'Google Chrome', u'window', u'slash']

[David Tseng, 2014/06/30 16:55:28]

Any chance NVDA could just use json for the log format?

[dmazzoni, 2014/07/15 06:09:58]

Happy to ask - but this seems robust enough for what we need.

+    """
+    lines = open(NVDA_LOGPATH).readlines()
+    regex = re.compile(r"u'((?:[^\'\\]|\\.)*)\'")
+    result = []
+    for line in lines:
+      for m in regex.finditer(line):
+        result.append(m.group(1))
+    return result
+
+  #
+  # Tests
+  #
+
+  def testTypingInOmnibox(self):
+    # Ctrl+A: Select all.
+    self._pywinauto_window.TypeKeys("^A")
+    time.sleep(1)

[David Tseng, 2014/06/30 16:55:29]

Going to be flakey; any way we could just listen to events from NVDA?

[dmazzoni, 2014/07/15 06:09:58]

I think I've removed the flakiness. I really like keeping these really
high-level and just focusing on key events and speech, not digging into anything
lower-level than that if possible.

+
+    # Type three characters.
+    self._pywinauto_window.TypeKeys("xyz")
+    time.sleep(1)
+
+    # Arrow back over two characters.
+    self._pywinauto_window.TypeKeys("{LEFT}")
+    time.sleep(1)
+    self._pywinauto_window.TypeKeys("{LEFT}")
+    time.sleep(1)
+
+    speech = self._GetSpeechFromNvdaLogFile()
+
+    self.assertIn('Address and search bar  edit', speech)
+    speech = speech[speech.index('Address and search bar  edit'):]
+
+    self.assertEqual(speech, [
+        'Address and search bar  edit',
+        'about:blank',
+        'selecting about:blank',
+        'x',
+        'y',
+        'z',
+        'z',
+        'unselecting ',
+        'y'])
+
+  def testFocusToolbarButton(self):
+    # Alt+Shift+T.
+    self._pywinauto_window.TypeKeys("%+T")
+    time.sleep(1)
+
+    speech = self._GetSpeechFromNvdaLogFile()
+    self.assertIn('Reload  button  Reload this page', speech)
+
+  def testReadAllOnPageLoad(self):
+    # Ctrl+A: Select all
+    self._pywinauto_window.TypeKeys("^A")
+    time.sleep(1)
+
+    # Load data url.
+    self._pywinauto_window.TypeKeys("data:text/html,Hello<p>World")
+    time.sleep(1)
+    self._pywinauto_window.TypeKeys("{ENTER}")
+    time.sleep(1)
+
+    speech = self._GetSpeechFromNvdaLogFile()
+
+    self.assertIn('document', speech)
+    speech = speech[speech.index('document'):]
+
+    self.assertEqual(speech, [
+        'document',
+        'Hello',
+        'World'])
+
+if __name__ == '__main__':
+  unittest.main()
+