[Telemetry] Add __enter__ & __exit__ methods for action_runner.Interaction.

BUG=475090

Review URL: https://codereview.chromium.org/1072443004

Cr-Commit-Position: refs/heads/master@{#324315}

tools/telemetry/telemetry/internal/actions/action_runner_unittest.py

 # Copyright 2014 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 unittest
 
 from telemetry.core import exceptions
 from telemetry.core.platform import tracing_category_filter
 from telemetry.core.platform import tracing_options
+from telemetry.core import util
 from telemetry import decorators
 from telemetry.internal.actions import page_action
 from telemetry.page import action_runner as action_runner_module
@@ -12,6 +14,9 @@ from telemetry.timeline import model
 from telemetry.unittest_util import tab_test_case
 from telemetry.web_perf import timeline_interaction_record as tir_module
 
+util.AddDirToPythonPath(util.GetTelemetryDir(), 'third_party', 'mock')
+import mock
+
 
 class ActionRunnerInteractionTest(tab_test_case.TabTestCase):
 
@@ -33,9 +38,9 @@ class ActionRunnerInteractionTest(tab_test_case.TabTestCase):
     options.enable_chrome_trace = True
     self._browser.platform.tracing_controller.Start(
         options, tracing_category_filter.CreateNoOverheadFilter())
-    interaction = action_runner.BeginInteraction('InteractionName',
-                                                 **interaction_kwargs)
-    interaction.End()
+    with action_runner.CreateInteraction('InteractionName',
+                                                 **interaction_kwargs):
+      pass
     trace_data = self._browser.platform.tracing_controller.Stop()
 
     records = self.GetInteractionRecords(trace_data)
@@ -248,3 +253,34 @@ class ActionRunnerTest(tab_test_case.TabTestCase):
     action_runner.SwipePage(direction='left', left_start_ratio=0.9)
     self.assertTrue(action_runner.EvaluateJavaScript(
         'document.body.scrollLeft') > 75)
+
+
+class InteractionTest(unittest.TestCase):
+
+  def setUp(self):
+    self.mock_action_runner = mock.Mock(action_runner_module.ActionRunner)
+
+  def testIssuingInteractionRecordCommand(self):
+    with action_runner_module.Interaction(
+        self.mock_action_runner, label='ABC', flags=[]):
+      pass
+    expected_calls = [
+        mock.call.ExecuteJavaScript('console.time("Interaction.ABC");'),
+        mock.call.ExecuteJavaScript('console.timeEnd("Interaction.ABC");')]
+    self.assertEqual(expected_calls, self.mock_action_runner.mock_calls)
+
+  def testExceptionRaisedInWithInteraction(self):
+    class FooException(Exception):
+      pass
+    # Test that the Foo exception raised in the with block is propagated to the
+    # caller.
+    with self.assertRaises(FooException):
+      with action_runner_module.Interaction(
+          self.mock_action_runner, label='ABC', flags=[]):
+        raise FooException()
+
+    # Test that the end console.timeEnd(...) isn't called because exception was
+    # raised.
+    expected_calls = [
+        mock.call.ExecuteJavaScript('console.time("Interaction.ABC");')]
+    self.assertEqual(expected_calls, self.mock_action_runner.mock_calls)

tools/telemetry/telemetry/page/action_runner.py

@@ -6,6 +6,7 @@ import logging
 import time
 import urlparse
 
+from telemetry.core import exceptions
 from telemetry.internal.actions.drag import DragAction
 from telemetry.internal.actions.javascript_click import ClickElementAction
 from telemetry.internal.actions.loop import LoopAction
@@ -34,6 +35,7 @@ class ActionRunner(object):
     action.WillRunAction(self._tab)
     action.RunAction(self._tab)
 
+  # TODO(nednguyen): remove this API when crbug.com/475090 is fixed.
   def BeginInteraction(self, label, repeatable=False):
     """Marks the beginning of an interaction record.
 
@@ -58,6 +60,7 @@ class ActionRunner(object):
     interaction.Begin()
     return interaction
 
+  # TODO(nednguyen): remove this API when crbug.com/475090 is fixed.
   def BeginGestureInteraction(self, label, repeatable=False):
     """Marks the beginning of a gesture-based interaction record.
 
@@ -78,6 +81,67 @@ class ActionRunner(object):
     """
     return self.BeginInteraction('Gesture_' + label, repeatable)
 
+  def CreateInteraction(self, label, repeatable=False):
+    """ Create an action.Interaction object that issues interaction record.
+
+    An interaction record is a labeled time period containing
+    interaction that developers care about. Each set of metrics
+    specified in flags will be calculated for this time period.
+
+    To mark the start of interaction record, call Begin() method on the returned
+    object. To mark the finish of interaction record, call End() method on
+    it. Or better yet, use the with statement to create an
+    interaction record that covers the actions in the with block.
+
+    e.g:
+      with action_runner.CreateInteraction('Animation-1'):
+        action_runner.TapElement(...)
+        action_runner.WaitForJavaScriptCondition(...)
+
+    Args:
+      label: A label for this particular interaction. This can be any
+          user-defined string, but must not contain '/'.
+      repeatable: Whether other interactions may use the same logical name
+          as this interaction. All interactions with the same logical name must
+          have the same flags.
+
+    Returns:
+      An instance of action_runner.Interaction
+    """
+    flags = []
+    if repeatable:
+      flags.append(timeline_interaction_record.REPEATABLE)
+
+    return Interaction(self._tab, label, flags)
+
+  def CreateGestureInteraction(self, label, repeatable=False):
+    """ Create an action.Interaction object that issues gesture-based
+    interaction record.
+
+    This is similar to normal interaction record, but it will
+    auto-narrow the interaction time period to only include the
+    synthetic gesture event output by Chrome. This is typically use to
+    reduce noise in gesture-based analysis (e.g., analysis for a
+    swipe/scroll).
+
+    The interaction record label will be prepended with 'Gesture_'.
+
+    e.g:
+      with action_runner.CreateGestureInteraction('Scroll-1'):
+        action_runner.ScrollPage()
+
+    Args:
+      label: A label for this particular interaction. This can be any
+          user-defined string, but must not contain '/'.
+      repeatable: Whether other interactions may use the same logical name
+          as this interaction. All interactions with the same logical name must
+          have the same flags.
+
+    Returns:
+      An instance of action_runner.Interaction
+    """
+    return self.CreateInteraction('Gesture_' + label, repeatable)
+
   def NavigateToPage(self, page, timeout_in_seconds=60):
     """Navigates to the given page.
 
@@ -624,6 +688,18 @@ class Interaction(object):
     self._flags = flags
     self._started = False
 
+  def __enter__(self):
+    self.Begin()
+    return self
+
+  def __exit__(self, exc_type, exc_value, traceback):
+    if exc_value is None:
+      self.End()
+    else:
+      logging.warning(
+          'Exception was raised in the with statement block, the end of '
+          'interaction record is not marked.')
+
   def Begin(self):
     assert not self._started
     self._started = True