Add video frames and volume tests

tools/chrome_proxy/webdriver/video.py

Index: tools/chrome_proxy/webdriver/video.py
diff --git a/tools/chrome_proxy/webdriver/video.py b/tools/chrome_proxy/webdriver/video.py
index ef02a0f278e79020b58dfa4e5c31c197b248389b..5d950d8b235796445e7714c0bfb801d87b635446 100644
--- a/tools/chrome_proxy/webdriver/video.py
+++ b/tools/chrome_proxy/webdriver/video.py
@@ -2,6 +2,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import time
+
 import common
 from common import TestDriver
 from common import IntegrationTest
@@ -40,5 +42,49 @@ class Video(IntegrationTest):
           self.assertHasChromeProxyViaHeader(response)
       self.assertTrue(saw_video_response, 'No video request seen in test!')
 
+  # Check the frames of a compressed video.
+  def testVideoFrames(self):
+    self.instrumentedVideoTest('http://check.googlezip.net/cacheable/video/buck_bunny_640x360_24fps_video.html')
+
+  # Check the audio volume of a compressed video.
+  def testVideoAudio(self):
+    self.instrumentedVideoTest('http://check.googlezip.net/cacheable/video/buck_bunny_640x360_24fps_audio.html')
+
+  def instrumentedVideoTest(self, url):
+    """Run an instrumented video test. The given page is reloaded up to some
+    maximum number of times until a compressed video is seen by ChromeDriver by
+    inspecting the network logs. Once that happens, test.ready is set and that
+    will signal the Javascript test on the page to begin. Once it is complete,
+    check the results.
+    """
+    # The maximum number of times to attempt to reload the page for a compressed
+    # video.
+    max_attempts = 10

[Tom Bergan, 2017/02/14 18:27:18]

Hopefully 10 attempts aren't actually necessary in practice! Do you have data on
how often this flakes?

[Robert Ogden, 2017/02/14 18:57:32]

Of the numerous times I've run it on my machine, it typically needs no more than
2 but I've seen it only as high as 4.

+    with TestDriver() as t:
+      t.AddChromeArg('--enable-spdy-proxy-auth')
+      loaded_compressed_video = False
+      attempts = 0
+      while not loaded_compressed_video and attempts < max_attempts:
+        t.LoadURL(url)
+        attempts += 1
+        for resp in t.GetHTTPResponses():
+          self.assertHasChromeProxyViaHeader(resp)

[Tom Bergan, 2017/02/14 18:27:18]

Will this assertion fail (and crash the test) on a flake? If so, it's better to
move this just after line 74.

[Robert Ogden, 2017/02/14 18:57:32]

Done.

+          if ('content-type' in resp.response_headers
+              and resp.response_headers['content-type'] == 'video/webm'):
+            loaded_compressed_video = True
+          else:
+            # Take a breath before requesting again.
+            time.sleep(1)
+      if attempts >= max_attempts:
+        self.fail('Could not get a compressed video after %d tries' % attempts)
+      t.ExecuteJavascriptStatement('test.ready = true')
+      wait_time = int(t.ExecuteJavascriptStatement('test.waitTime'))
+      t.WaitForJavascriptExpression('test.metrics.complete', wait_time)
+      metrics = t.ExecuteJavascriptStatement('test.metrics')
+      if not metrics['complete']:
+        raise Exception('Test not complete after %d seconds.' % wait_time)
+      if metrics['failed']:
+        raise Exception('Test failed!')
+
 if __name__ == '__main__':
   IntegrationTest.RunAllTests()