text: # 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
  
  from collections import namedtuple
  from telemetry.internal.results import page_test_results
  from telemetry.page import page
  from telemetry.web_perf.metrics import jitter_timeline
  from telemetry.web_perf import timeline_interaction_record
  
  
  FakeEvent = namedtuple('Event', 'name, start, end, thread_duration, args')
  Interaction = timeline_interaction_record.TimelineInteractionRecord
  TEST_INTERACTION_LABEL = 'Action_TestInteraction'
  JITTER_EVENT_NAME = 'jitter'
  
  def GetJitterMetrics(events, interactions):
    results = page_test_results.PageTestResults()
    test_page = page.Page('file://blank.html')
    results.WillRunPage(test_page)
    jitter_timeline.JitterTimelineMetric()._AddJitterResultsInternal(
        events, interactions, results)
    return_dict = dict((value.name, value.values) for value in
                       results.current_page_run.values)
    results.DidRunPage(test_page)
    return return_dict
  
  def FakeJitterEvent(start, end, value, thread_duration=None):
    if not thread_duration:
      thread_duration = end - start
    return FakeEvent(jitter_timeline.JITTER_EVENT_NAME,
            start, end, thread_duration, {'value':value})
  
  def TestInteraction(start, end):
    return Interaction(TEST_INTERACTION_LABEL, start, end)
  
  
  class JitterTimelineMetricUnitTest(unittest.TestCase):
    def testJitterMetric(self):
      events = [FakeJitterEvent(0, 1, 10),
                FakeJitterEvent(5, 10, 5),
                FakeJitterEvent(15, 34, 45)]
      interactions = [TestInteraction(4, 14)]
      # The first and the last event do not start during the interaction, so
      # they are ignored. The second event starts during the interaction, and its
      # value is 5.
      self.assertEqual({'jitter-amount': [5]},
          GetJitterMetrics(events, interactions))
  