Implement the Lo-Fi cache related integration tests with ChromeDriver

tools/chrome_proxy/webdriver/lofi.py

Index: tools/chrome_proxy/webdriver/lofi.py
diff --git a/tools/chrome_proxy/webdriver/lofi.py b/tools/chrome_proxy/webdriver/lofi.py
index a0753b1ad6c2cb54e29cec1ad0e7764803ae653b..8b2fd5d43ae3ba547c6d779f1ebed029fe47b098 100644
--- a/tools/chrome_proxy/webdriver/lofi.py
+++ b/tools/chrome_proxy/webdriver/lofi.py
@@ -19,7 +19,6 @@ class LoFi(IntegrationTest):
       # Disable server experiments such as tamper detection.
       test_driver.AddChromeArg('--data-reduction-proxy-server-experiments-'
                                'disabled')
-      test_driver.AddChromeArg('--disable-quic')
 
       test_driver.LoadURL('http://check.googlezip.net/static/index.html')
 
@@ -29,15 +28,8 @@ class LoFi(IntegrationTest):
           continue
         if not response.request_headers:
           continue
-        self.assertHasChromeProxyViaHeader(response)
-        content_length = response.response_headers['content-length']
-        cpat_request = response.request_headers['chrome-proxy-accept-transform']
-        cpct_response = response.response_headers[
-                          'chrome-proxy-content-transform']
-        if ('empty-image' in cpct_response):
+        if (self.assertLoFiResponse(response, True)):
           lofi_responses = lofi_responses + 1
-          self.assertIn('empty-image', cpat_request)
-          self.assertTrue(int(content_length) < 100)
 
       # Verify that Lo-Fi responses were seen.
       self.assertNotEqual(0, lofi_responses)
@@ -74,5 +66,79 @@ class LoFi(IntegrationTest):
       # Verify that a Lite Page response for the main frame was seen.
       self.assertEqual(1, lite_page_responses)
 
+  # Checks that Lo-Fi placeholder images are not loaded from cache on page
+  # reloads when Lo-Fi mode is disabled or data reduction proxy is disabled.
+  # First a test page is opened with Lo-Fi and chrome proxy enabled. This allows
+  # Chrome to cache the Lo-Fi placeholder image. The browser is restarted with
+  # chrome proxy disabled and the same test page is loaded. This second page
+  # load should not pick the Lo-Fi placeholder from cache and original image
+  # should be loaded. Finally, the browser is restarted with chrome proxy
+  # enabled and Lo-Fi disabled and the same test page is loaded. This third page
+  # load should not pick the Lo-Fi placeholder from cache and original image
+  # should be loaded.
+  def testLoFiCacheBypass(self):
+    with TestDriver() as test_driver:
+      # First page load, enable Lo-Fi and chrome proxy. Disable server
+      # experiments such as tamper detection. This test should be run with
+      # --profile-type=default command line for the same user profile and cache
+      # to be used across the two page loads.
+      test_driver.AddChromeArg('--enable-spdy-proxy-auth')
+      test_driver.AddChromeArg('--data-reduction-proxy-lo-fi=always-on')
+      test_driver.AddChromeArg('--profile-type=default')
+      test_driver.AddChromeArg('--data-reduction-proxy-server-experiments-'
+                               'disabled')
+
+      test_driver.LoadURL('http://check.googlezip.net/cacheable/test.html')
+
+      lofi_responses = 0
+      for response in test_driver.GetHTTPResponses():
+        if not response.url.endswith('png'):
+          continue
+        if not response.request_headers:
+          continue
+        if (self.assertLoFiResponse(response, True)):
+          lofi_responses = lofi_responses + 1
+
+      # Verify that Lo-Fi responses were seen.
+      self.assertNotEqual(0, lofi_responses)
+
+      # Second page load with the chrome proxy off.
+      test_driver._StopDriver()
+      test_driver.RemoveChromeArg('--enable-spdy-proxy-auth')
+      test_driver.LoadURL('http://check.googlezip.net/cacheable/test.html')
+
+      responses = 0
+      for response in test_driver.GetHTTPResponses():
+        if not response.url.endswith('png'):
+          continue
+        if not response.request_headers:
+          continue
+        responses = responses + 1
+        self.assertNotHasChromeProxyViaHeader(response)
+        self.assertLoFiResponse(response, False)
+
+      # Verify that responses were seen.
+      self.assertNotEqual(0, responses)
+
+      # Third page load with the chrome proxy on and Lo-Fi off.
+      test_driver._StopDriver()
+      test_driver.AddChromeArg('--enable-spdy-proxy-auth')
+      test_driver.RemoveChromeArg('--data-reduction-proxy-lo-fi=always-on')
+      test_driver.AddChromeArg('--data-reduction-proxy-lo-fi=disabled')
+      test_driver.LoadURL('http://check.googlezip.net/cacheable/test.html')
+
+      responses = 0
+      for response in test_driver.GetHTTPResponses():
+        if not response.url.endswith('png'):
+          continue
+        if not response.request_headers:
+          continue
+        responses = responses + 1
+        self.assertHasChromeProxyViaHeader(response)
+        self.assertLoFiResponse(response, False)
+
+      # Verify that responses were seen.
+      self.assertNotEqual(0, responses)
+
 if __name__ == '__main__':
   IntegrationTest.RunAllTests()