Add Video.testVideoSeeking test.

tools/chrome_proxy/webdriver/video.py

 # Copyright 2017 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.
 
 import time
 
 import common
 from common import TestDriver
 from common import IntegrationTest
 from common import ParseFlags
@@ skipping 42 matching lines @@
   @Slow
   def testVideoMetrics(self):
     expected = {
       'duration': 3.124,
       'webkitDecodedFrameCount': 54.0,
       'videoWidth': 1280.0,
       'videoHeight': 720.0
     }
     with TestDriver() as t:
       t.AddChromeArg('--enable-spdy-proxy-auth')
-      t.LoadURL('http://check.googlezip.net/cacheable/video/buck_bunny_tiny.html')
+      t.LoadURL(
+          'http://check.googlezip.net/cacheable/video/buck_bunny_tiny.html')
       # Check request was proxied and we got a compressed video back.
       for response in t.GetHTTPResponses():
         self.assertHasChromeProxyViaHeader(response)
         if ('content-type' in response.response_headers
             and 'video' in response.response_headers['content-type']):
           self.assertEqual('video/webm',
             response.response_headers['content-type'])
       if ParseFlags().android:
         t.FindElement(By.TAG_NAME, "video").click()
       else:
         t.ExecuteJavascriptStatement(
           'document.querySelectorAll("video")[0].play()')
       # Wait for the video to finish playing, plus some headroom.
       time.sleep(5)
       # Check each metric against its expected value.
       for metric in expected:
         actual = float(t.ExecuteJavascriptStatement(
           'document.querySelectorAll("video")[0].%s' % metric))
         self.assertAlmostEqual(expected[metric], actual, msg="Compressed video "
           "metric doesn't match expected! Metric=%s Expected=%f Actual=%f"
           % (metric, expected[metric], actual), places=None, delta=0.001)
 
+  # Check that the compressed video can be seeked. Use a slow network to ensure
+  # the entire video isn't downloaded before we have a chance to seek.
+  #
+  # This test cannot run on android because of control_network_connection=True.
+  # That option is used to reduce flakes that might happen on fast networks,
+  # where the video is completely downloaded before a seeking request can be
+  # sent. The test can be manually simulated by the following steps: set network
+  # emulation in DevTools on Android (via device inspector), load a video, pause
+  # the video, then seek and verify the seek continues to play the video.
+  @Slow
+  @NotAndroid
+  def testVideoSeeking(self):
+    with TestDriver(control_network_connection=True) as t:
+      t.SetNetworkConnection("3G")
+      t.AddChromeArg('--enable-spdy-proxy-auth')
+      t.LoadURL(
+          'http://check.googlezip.net/cacheable/video/'+
+          'buck_bunny_640x360_24fps.html')
+      # Play, pause, seek to 1s before the end, play again.
+      t.ExecuteJavascript(
+        '''
+        window.testDone = false;
+        const v = document.getElementsByTagName("video")[0];
+        let first = true;
+        v.onplaying = function() {
+          if (first) {
+            v.pause();
+            first = false;
+          } else {
+            window.testDone = true;
+          }
+        };
+        v.onpause = function() {
+          if (v.currentTime < v.duration) {
+            v.currentTime = v.duration-1;
+            v.play();
+          }
+        };
+        v.play();
+        ''')
+      t.WaitForJavascriptExpression('window.testDone', 10)
+      # Check request was proxied and we got a compressed video back.
+      # We expect to make multiple requests for the video: ensure they
+      # all have the same ETag.
+      video_etag = None
+      num_partial_requests = 0
+      for response in t.GetHTTPResponses():
+        self.assertHasChromeProxyViaHeader(response)
+        rh = response.response_headers
+        if ('content-type' in rh and 'video' in rh['content-type']):
+          self.assertTrue('etag' in rh),
+          self.assertEqual('video/webm', rh['content-type'])
+          if video_etag == None:
+            video_etag = rh['etag']
+          else:
+            self.assertEqual(video_etag, rh['etag'])
+          if ('range' in response.request_headers and
+              response.request_headers['range'] != 'bytes=0-'):
+            num_partial_requests += 1
+      # Also make sure that we had at least one partial Range request.
+      self.assertGreaterEqual(num_partial_requests, 1)
+
   # Check the frames of a compressed video.
   @Slow
   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.
   @NotAndroid
   @Slow
   def testVideoAudio(self):
     self.instrumentedVideoTest('http://check.googlezip.net/cacheable/video/buck_bunny_640x360_24fps_audio.html')
@@ skipping 46 matching lines @@
         # Video won't auto play on Android, so give it a click.
         t.FindElement(By.ID, 'player').click()
       t.WaitForJavascriptExpression(
         'window.playerState == YT.PlayerState.PLAYING', 30)
       for response in t.GetHTTPResponses():
         if not response.url.startswith('https'):
           self.assertHasChromeProxyViaHeader(response)
 
 if __name__ == '__main__':
   IntegrationTest.RunAllTests()