tools/perf/metrics/cpu_unittest.py

   1 # Copyright 2013 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 import unittest
   6
   7 from metrics import cpu
   8
   9 # Testing private method.
  10 # pylint: disable=W0212
  11 class CpuMetricTest(unittest.TestCase):
  12   def testSubtractCpuStats(self):
  13     # The result computed is a ratio of cpu time used to time elapsed.
  14     start = {'Browser': {'CpuProcessTime': 0, 'TotalTime': 0}}
  15     end = {'Browser': {'CpuProcessTime': 5, 'TotalTime': 20}}
  16     self.assertEqual({'Browser': 0.25}, cpu._SubtractCpuStats(end, start))
  17
  18     # An error is thrown if the args are called in the wrong order.
  19     self.assertRaises(AssertionError, cpu._SubtractCpuStats, start, end)
  20
  21     # An error is thrown if there's a process type in end that's not in start.
  22     end['Renderer'] = {'CpuProcessTime': 2, 'TotalTime': 20}
  23     self.assertRaises(AssertionError, cpu._SubtractCpuStats, end, start)
  24
  25     # A process type will be ignored if there's an empty dict for start or end.
  26     start['Renderer'] = {}
  27     self.assertEqual({'Browser': 0.25}, cpu._SubtractCpuStats(end, start))
  28
  29     # Results for multiple process types can be computed.
  30     start['Renderer'] = {'CpuProcessTime': 0, 'TotalTime': 0}
  31     self.assertEqual({'Browser': 0.25, 'Renderer': 0.1},
  32                      cpu._SubtractCpuStats(end, start))
  33
  34     # Test 32-bit overflow.
  35     start = {'Browser': {'CpuProcessTime': 0, 'TotalTime': 2**32 - 20}}
  36     end = {'Browser': {'CpuProcessTime': 5, 'TotalTime': 20}}
  37     self.assertEqual({'Browser': 0.125}, cpu._SubtractCpuStats(end, start))
  38     self.assertRaises(AssertionError, cpu._SubtractCpuStats, start, end)
  39