Add data reduction proxy integration tests for video compression.

tools/chrome_proxy/integration_tests/chrome_proxy_metrics.py

Index: tools/chrome_proxy/integration_tests/chrome_proxy_metrics.py
diff --git a/tools/chrome_proxy/integration_tests/chrome_proxy_metrics.py b/tools/chrome_proxy/integration_tests/chrome_proxy_metrics.py
index f21e3d8f3ed72c42adeeb8bbba5beae1aa8de6f5..a3eb12d5177fb20710604708a0e97e93c251c95f 100644
--- a/tools/chrome_proxy/integration_tests/chrome_proxy_metrics.py
+++ b/tools/chrome_proxy/integration_tests/chrome_proxy_metrics.py
@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import logging
+import os
 import time
 
 from integration_tests import network_metrics
@@ -18,7 +19,7 @@ CHROME_PROXY_VIA_HEADER = 'Chrome-Compression-Proxy'
 
 
 class ChromeProxyResponse(network_metrics.HTTPResponse):
-  """ Represents an HTTP response from a timeleine event."""
+  """ Represents an HTTP response from a timeline event."""
   def __init__(self, event):
     super(ChromeProxyResponse, self).__init__(event)
 
@@ -81,6 +82,7 @@ class ChromeProxyResponse(network_metrics.HTTPResponse):
         return True
     return False
 
+
 class ChromeProxyMetric(network_metrics.NetworkMetric):
   """A Chrome proxy timeline metric."""
 
@@ -559,3 +561,88 @@ class ChromeProxyMetric(network_metrics.NetworkMetric):
         results.current_page, 'bypass', 'count', bypass_count))
     results.AddValue(scalar.ScalarValue(
         results.current_page, 'via', 'count', via_count))
+

[sclittle, 2015/04/10 23:01:49]

2 blank lines

[Tom Bergan, 2015/04/10 23:41:05]

Done.

+class ChromeProxyVideoMetric(network_metrics.NetworkMetric):
+  """A Chrome proxy video metric."""

[sclittle, 2015/04/10 23:01:50]

Could you add a more detailed description of the class here?

[Tom Bergan, 2015/05/01 23:48:28]

Done.

+  def __init__(self, tab):
+    super(ChromeProxyVideoMetric, self).__init__()
+    with open(os.path.join(os.path.dirname(__file__), 'videowrapper.js')) as f:
+      js = f.read()
+      tab.ExecuteJavaScript(js)
+
+  def Start(self, page, tab):
+    tab.ExecuteJavaScript('window.__chromeProxyCreateVideoWrappers()')
+    self.videoMetrics = None
+    super(ChromeProxyVideoMetric, self).Start(page, tab)
+
+  def Stop(self, page, tab):
+    tab.WaitForJavaScriptExpression('window.__chromeProxyVideoLoaded', 30)
+    m = tab.EvaluateJavaScript('window.__chromeProxyVideoMetrics')
+    # Now wait for the video to stop playing.

[sclittle, 2015/04/10 23:01:50]

nit: this code seems kinda dense, could you add some blank lines to separate
major blocks?

[Tom Bergan, 2015/04/10 23:41:05]

Done.

+    # Give it 2x the total duration to account for buffering.
+    waitTime = 2 * m['video_duration']
+    tab.WaitForJavaScriptExpression('window.__chromeProxyVideoEnded', waitTime)
+    # Load the final metrics.
+    m = tab.EvaluateJavaScript('window.__chromeProxyVideoMetrics')
+    self.videoMetrics = m
+    # Cast this to an integer as it is often approximate (for an unknown reason)
+    m['video_duration'] = int(m['video_duration'])
+    super(ChromeProxyVideoMetric, self).Stop(page, tab)
+
+  def ResponseFromEvent(self, event):
+    return ChromeProxyResponse(event)
+
+  def AddResults(self, tab, results):
+    raise NotImplementedError
+
+  def AddResultsForProxied(self, tab, results):
+    return self._AddResultsShared('proxied', tab, results)

[sclittle, 2015/04/10 23:01:49]

This 'proxied' string is used in a bunch of places, could it be a constant? Same
with 'direct'.

[Tom Bergan, 2015/04/10 23:41:05]

Done.

+
+  def AddResultsForDirect(self, tab, results):
+    return self._AddResultsShared('direct', tab, results)
+
+  def _AddResultsShared(self, kind, tab, results):
+    def err(s):
+      raise ChromeProxyMetricException, s
+
+    # Should have played the video.
+    if not self.videoMetrics['ready']:
+      err('%s: video not played' % kind)
+
+    # Should have an HTTP response for the video.
+    wantContentType = 'video/webm' if kind == 'proxied' else 'video/mp4'
+    found = False
+    for r in self.IterResponses(tab):
+      resp = r.response
+      if kind == 'direct' and r.HasChromeProxyViaHeader():
+        err('%s: page has proxied Via header' % kind)
+      if resp.GetHeader('Content-Type') != wantContentType:
+        continue
+      if found:
+        err('%s: multiple video responses' % kind)
+      found = True

[sclittle, 2015/04/10 23:01:50]

nit: again, code seems kinda dense; adding some blank lines where appropriate
would make this easier to read.

[Tom Bergan, 2015/05/01 23:48:28]

Done.

+      cl = resp.GetHeader('Content-Length')
+      xocl = resp.GetHeader('X-Original-Content-Length')
+      if cl != None:
+        self.videoMetrics['content_length_header'] = int(cl)
+      if xocl != None:
+        self.videoMetrics['x_original_content_length_header'] = int(xocl)
+      # Should have CL always.
+      if cl == None:
+        err('%s: missing ContentLength' % kind)
+      # Proxied: should have CL < XOCL
+      # Direct: should not have XOCL
+      if kind == 'proxied':
+        if xocl == None or int(cl) >= int(xocl):
+          err('%s: bigger response (%s > %s)' % (kind, str(cl), str(xocl)))
+      else:
+        if xocl != None:
+          err('%s: has XOriginalContentLength' % kind)
+
+    if not found:
+      err('%s: missing video response' % kind)
+
+    # Finally, add all the metrics to the results.
+    for (k,v) in self.videoMetrics.iteritems():
+      k = "%s_%s" % (k, kind)
+      results.AddValue(scalar.ScalarValue(results.current_page, k, "", v))

[sclittle, 2015/04/10 23:01:49]

Could you just call results.AddValue(...) inline above instead of building up a
dict of results?

[Tom Bergan, 2015/05/01 23:48:28]

This dict is used by ChromeProxyVideoValidation (in
chrome_proxy_measurements.py) when comparing proxied and direct fetches. I could
just call results.AddValue instead of making this dict, but then it becomes
harder to do the comparison in ChromeProxyVideoValidation because it's more
cumbersome to extract values from results.