Add ValidateAndMeasurePage to PageTest; this is a replacement for both...

Add ValidateAndMeasurePage to PageTest; this is a replacement for both ValidatePage and MeasurePage.

Usage will be cleaned up in subsequent patch(es), along with
killing PageMeasurement.

BUG=383635

Review URL: https://codereview.chromium.org/452523002

Cr-Commit-Position: refs/heads/master@{#288291}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288291 0039d316-1c4b-4281-b951-d872f2087c98

tools/telemetry/telemetry/page/page_test.py

@@ -27,14 +27,11 @@ class MeasurementFailure(Failure):
 class PageTest(command_line.Command):
   """A class styled on unittest.TestCase for creating page-specific tests.
 
-  This class also support running a measurement by default (but can be
-  overridden by overriding ValidatePage method).
-
-  To use this for measurement, subclass from the measurement and
-  override MeasurePage. For example:
+  Test should override ValidateAndMeasurePage to perform test
+  validation and page measurement as necessary.
 
      class BodyChildElementMeasurement(PageTest):
-       def MeasurePage(self, page, tab, results):
+       def ValidateAndMeasurePage(self, page, tab, results):
          body_child_count = tab.EvaluateJavaScript(
              'document.body.children.length')
          results.AddValue(scalar.ScalarValue(
@@ -47,7 +44,7 @@ class PageTest(command_line.Command):
        def AddCommandLineArgs(parser):
          parser.add_option('--element', action='store', default='body')
 
-        def MeasurePage(self, page, tab, results):
+       def ValidateAndMeasurePage(self, page, tab, results):
          body_child_count = tab.EvaluateJavaScript(
              'document.querySelector('%s').children.length')
          results.AddValue(scalar.ScalarValue(
@@ -263,26 +260,19 @@ class PageTest(command_line.Command):
     """Override to examine the page set before the test run.  Useful for
     example to validate that the pageset can be used with the test."""
 
-  def ValidatePage(self, page, tab, results):
-    """Override to check the actual test assertions.
-
-    This is where most your test logic should go. By default it runs
-    self.MeasurePage.
-    """
-    self.MeasurePage(page, tab, results)
-
-  def MeasurePage(self, page, tab, results):
-    """Override to actually measure the page's performance.
+  def ValidateAndMeasurePage(self, page, tab, results):
+    """Override to check test assertions and perform measurement.
 
-    Should call results.AddValue(...) for each result. Can raise an
-    exception of add a failure.FailureValue on failure.
+    When adding measurement results, call results.AddValue(...) for
+    each result. Raise an exception or add a failure.FailureValue on
+    failure. page_test.py also provides several base exception classes
+    to use.
 
     Prefer metric value names that are in accordance with python
     variable style. e.g., metric_name. The name 'url' must not be used.
 
     Put together:
-
-       def MeasurePage(self, page, tab, results):
+      def ValidateAndMeasurePage(self, page, tab, results):
         res = tab.EvaluateJavaScript('2+2')
         if res != 4:
           raise Exception('Oh, wow.')
@@ -294,6 +284,16 @@ class PageTest(command_line.Command):
       tab: A telemetry.core.Tab instance.
       results: A telemetry.results.PageTestResults instance.
     """
+    # TODO(chrishenry): Switch to raise NotImplementedError() when
+    # subclasses no longer override ValidatePage/MeasurePage.
+    self.ValidatePage(page, tab, results)
+
+  def ValidatePage(self, page, tab, results):
+    """DEPRECATED: Use ValidateAndMeasurePage instead."""
+    self.MeasurePage(page, tab, results)
+
+  def MeasurePage(self, page, tab, results):
+    """DEPRECATED: Use ValidateAndMeasurePage instead."""
 
   def RunPage(self, page, tab, results):
     # Run actions.
@@ -306,8 +306,7 @@ class PageTest(command_line.Command):
       self._RunMethod(page, self._action_name_to_run, action_runner)
     self.DidRunActions(page, tab)
 
-    # Run validator.
-    self.ValidatePage(page, tab, results)
+    self.ValidateAndMeasurePage(page, tab, results)
 
   def _RunMethod(self, page, method_name, action_runner):
     if hasattr(page, method_name):

tools/telemetry/telemetry/page/page_test_unittest.py

@@ -10,7 +10,7 @@ from telemetry.page import page_test
 
 
 class DoNothingPageTest(page_test.PageTest):
-  def ValidatePage(self, *_):
+  def ValidateAndMeasurePage(self, *_):
     pass
 
 
@@ -22,8 +22,8 @@ class TestPage(page_module.Page):
   def RunActionToRun(self, _):
     self.run_action_to_run_called = True
 
-class PageTestUnitTest(unittest.TestCase):
 
+class PageTestUnitTest(unittest.TestCase):
   def testRunActions(self):
     test = DoNothingPageTest('RunActionToRun')
     page = TestPage('file://blank.html', None, util.GetUnittestDataDir())