Re-implements start_with_url.* benchmarks as start_with_url2.* using TBM

tools/telemetry/telemetry/web_perf/metrics/startup_unittest.py

+# Copyright 2015 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
+
+import telemetry.timeline.event as timeline_event
+from telemetry.testing import test_page_test_results
+from telemetry.web_perf.metrics import startup
+
+
+class StartupTimelineMetricTest(unittest.TestCase):
+
+  def setUp(self):
+    self.events = []
+
+  def AddEvent(self, event_name, start, duration=None):
+    event = timeline_event.TimelineEvent('my_category', event_name,
+                                         start, duration)
+    self.events.append(event)
+
+  # pylint: disable=W0201
+  def RunAggregator(self):

[nednguyen, 2015/11/18 18:23:13]

nits: s/RunAggregator/ComputeStartupMetrics

[gabadie, 2015/11/18 19:16:32]

Done.

+    results = test_page_test_results.TestPageTestResults(self)
+
+    # Create a mock model usable by StartupTimelineMetric.AddWholeTraceResults()
+    def GenerateEvents(event_predicate):

[eakuefner, 2015/11/18 18:39:53]

Sorry, but I disagree with pasko here. Please change this back: it will be
consistent with IterAllEvents and with the general idea that is pervasive in
tracing, of iterating through collections of events.

[eakuefner, 2015/11/18 18:41:11]

Through I do agree that it should be IterateEvents rather than iterate_events:
we name methods with camel case and properties with lowercase and underscores.

[pasko, 2015/11/18 18:56:46]

up to you, of course

[gabadie, 2015/11/18 19:16:32]

Done.

+      for event in self.events:
+        if event_predicate(event):
+          yield event
+    class MockClass(object):
+      pass
+    model = MockClass()
+    model.browser_process = MockClass()
+    model.browser_process.parent = MockClass()
+    model.browser_process.parent.IterAllEvents = GenerateEvents
+
+    startup.StartupTimelineMetric().AddWholeTraceResults(model, results)
+    return results
+
+  def testUntrackedvents(self):
+    # Code coverage for untracked events, to make sure there is nothing wrong
+    # going on.
+    self.AddEvent('uknown_event_0', 0)
+    self.AddEvent('uknown_event_1', 1)
+    self.RunAggregator()
+
+  def testInstantEventsBasedValue(self):
+    # Test case with instant events to measure the duration between the first
+    # occurrences of two distinct events.
+    START0 = 7
+    START1 = 8
+    DURATION0 = 17
+    DURATION1 = 18
+
+    # Generate duplicated events to make sure we consider only the first one.
+    self.AddEvent(startup._MAIN_ENTRY_POINT, START0)
+    self.AddEvent(startup._MAIN_ENTRY_POINT, START1)
+    self.AddEvent('loadEventEnd', START0 + DURATION0)
+    self.AddEvent('loadEventEnd', START1 + DURATION1)
+
+    results = self.RunAggregator()
+    results.AssertHasPageSpecificScalarValue('foreground_tab_load_complete',
+        'ms', DURATION0)
+
+  def testBeginEndEventsBasedValue(self):
+    # Test case to get the duration of the first occurrence of a duration event.
+    DURATION = 13
+
+    # Generate duplicated events to make sure we consider only the first one.
+    self.AddEvent('Startup.BrowserMessageLoopStartTimeFromMainEntry', 5,
+        DURATION)
+    self.AddEvent('Startup.BrowserMessageLoopStartTimeFromMainEntry', 6,
+        DURATION + 2)
+
+    results = self.RunAggregator()
+    results.AssertHasPageSpecificScalarValue('messageloop_start_time', 'ms',
+        DURATION)

[nednguyen, 2015/11/18 18:23:13]

Can you also add test coverage for open_tabs_time,
first_non_empty_paint_time,..?

[gabadie, 2015/11/18 19:16:32]

Done.