[Telemetry] Adding Memory Timeline Metric

tools/telemetry/telemetry/web_perf/metrics/memory_timeline_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
+
+from telemetry.internal.results import page_test_results
+from telemetry.page import page
+from telemetry.web_perf.metrics import memory_timeline
+from telemetry.web_perf import timeline_interaction_record
+
+
+class MockMemoryDump(object):

[eakuefner, 2015/06/25 15:56:20]

Try using the mock library instead of mocking these classes by hand.

Check out tab_switching_unittest.py in
https://codereview.chromium.org/1152763002 to see how Dean imports the library
(since there's a magic incantation), and then uses it to mock his classes.
(Patchset 4 to see how he was doing it by hand before).

[perezju, 2015/06/26 11:34:52]

Done. Thanks for the suggestion, does look much cleaner.

+  def __init__(self, start, end, value):
+    self.start = start
+    self.end = end
+    # For simplicity, we tuck the same value on all reported metrics.

[eakuefner, 2015/06/25 15:56:20]

I'm confused about what "tuck" means here.

[perezju, 2015/06/26 11:34:52]

I re-phrased this a bit.

+    # The correctness of reported values should be tested in MemoryDumpEvent.
+    self.has_mmaps = value is not None
+    if self.has_mmaps:
+      self._stats = {name: value for name in memory_timeline.REPORTED_METRICS}
+    else:
+      self._stats = dict.fromkeys(memory_timeline.REPORTED_METRICS, 0)
+
+  def GetStatsSummary(self):
+    return self._stats
+
+
+class MockModel(object):
+  def __init__(self, events):
+    assert events
+    self._memory_dump_events = events
+
+  def IterMemoryDumpEvents(self, reverse=False):
+    if reverse:
+      return reversed(self._memory_dump_events)
+    else:
+      return iter(self._memory_dump_events)
+
+
+def TestInteraction(start, end):
+  return timeline_interaction_record.TimelineInteractionRecord(
+      'Action_TestInteraction', start, end)
+
+
+class MemoryTimelineMetricUnitTest(unittest.TestCase):
+  def getMetricValue(self, events, interactions):
+    def strip_prefix(key, prefix):
+      self.assertTrue(key.startswith(prefix))
+      return key[len(prefix):]
+
+    results = page_test_results.PageTestResults()
+    test_page = page.Page('http://google.com')
+    results.WillRunPage(test_page)
+    metric = memory_timeline.MemoryTimelineMetric()
+    metric.AddResults(MockModel(events), None, interactions, results)
+    result_dict = {strip_prefix(v.name, 'memory_infra_'): v.value
+                   for v in results.current_page_run.values}
+    results.DidRunPage(test_page)
+    # REPORTED_METRICS are exactly the ones reported
+    self.assertItemsEqual(memory_timeline.REPORTED_METRICS,
+                          result_dict.keys())
+    values = set(result_dict.values())
+    # all values should be the same in our simple test
+    self.assertEquals(1, len(values))
+    return values.pop()
+
+  def testSingleMemoryDump(self):
+    events = [MockMemoryDump(2, 4, 123)]
+    interactions = [TestInteraction(1, 10)]
+    self.assertEquals(123,
+                      self.getMetricValue(events, interactions))
+
+  def testMultipleMemoryDumps(self):
+    events = [MockMemoryDump(2, 4, 123),
+              MockMemoryDump(5, 6, 456)]
+    interactions = [TestInteraction(1, 10)]
+    self.assertEquals(456,
+                      self.getMetricValue(events, interactions))
+
+  def testMultipleInteractions_withDumpInSecond(self):
+    events = [MockMemoryDump(2, 4, 123),
+              MockMemoryDump(5, 6, 456),
+              MockMemoryDump(13, 14, 789)]
+    interactions = [TestInteraction(1, 10),
+                    TestInteraction(12, 15)]
+    self.assertEquals(789,
+                      self.getMetricValue(events, interactions))
+
+  def testMultipleInteractions_withoutDumpInSecond(self):
+    events = [MockMemoryDump(2, 4, 123),
+              MockMemoryDump(5, 6, 456),
+              MockMemoryDump(11, 12, 789)]
+    interactions = [TestInteraction(1, 10),
+                    TestInteraction(12, 15)]
+    self.assertEquals(456,
+                      self.getMetricValue(events, interactions))
+
+  def testMemoryDumpsOutsideInteractionIgnored(self):
+    events = [MockMemoryDump(0, 1, 555),
+              MockMemoryDump(2, 4, 123),
+              MockMemoryDump(5, 6, 456),
+              MockMemoryDump(8, 11, 789)]
+    interactions = [TestInteraction(1, 10)]
+    self.assertEquals(456,
+                      self.getMetricValue(events, interactions))
+
+  def testNoMemoryDumps(self):
+    events = [MockMemoryDump(0, 1, 555),
+              MockMemoryDump(8, 11, 789)]
+    interactions = [TestInteraction(1, 10)]
+    self.assertEquals(None,
+                      self.getMetricValue(events, interactions))
+
+  def testNoMmapsIgnoredMemoryDumps(self):
+    events = [MockMemoryDump(2, 4, 123),
+              MockMemoryDump(5, 6, None)]
+    interactions = [TestInteraction(1, 10)]
+    self.assertEquals(123,
+                      self.getMetricValue(events, interactions))