base/metrics/bucket_ranges_unittest.cc

   1 // Copyright (c) 2012 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 #include "base/metrics/bucket_ranges.h"
   6
   7 #include "testing/gtest/include/gtest/gtest.h"
   8
   9 namespace base {
  10 namespace {
  11
  12 TEST(BucketRangesTest, NormalSetup) {
  13   BucketRanges ranges(5);
  14   ASSERT_EQ(5u, ranges.size());
  15
  16   for (int i = 0; i < 5; i++) {
  17     EXPECT_EQ(0, ranges.range(i));
  18   }
  19   EXPECT_EQ(0u, ranges.checksum());
  20
  21   ranges.set_range(3, 100);
  22   EXPECT_EQ(100, ranges.range(3));
  23 }
  24
  25 TEST(BucketRangesTest, Equals) {
  26   // Compare empty ranges.
  27   BucketRanges ranges1(3);
  28   BucketRanges ranges2(3);
  29   BucketRanges ranges3(5);
  30
  31   EXPECT_TRUE(ranges1.Equals(&ranges2));
  32   EXPECT_FALSE(ranges1.Equals(&ranges3));
  33   EXPECT_FALSE(ranges2.Equals(&ranges3));
  34
  35   // Compare full filled ranges.
  36   ranges1.set_range(0, 0);
  37   ranges1.set_range(1, 1);
  38   ranges1.set_range(2, 2);
  39   ranges1.set_checksum(100);
  40   ranges2.set_range(0, 0);
  41   ranges2.set_range(1, 1);
  42   ranges2.set_range(2, 2);
  43   ranges2.set_checksum(100);
  44
  45   EXPECT_TRUE(ranges1.Equals(&ranges2));
  46
  47   // Checksum does not match.
  48   ranges1.set_checksum(99);
  49   EXPECT_FALSE(ranges1.Equals(&ranges2));
  50   ranges1.set_checksum(100);
  51
  52   // Range does not match.
  53   ranges1.set_range(1, 3);
  54   EXPECT_FALSE(ranges1.Equals(&ranges2));
  55 }
  56
  57 TEST(BucketRangesTest, Checksum) {
  58   BucketRanges ranges(3);
  59   ranges.set_range(0, 0);
  60   ranges.set_range(1, 1);
  61   ranges.set_range(2, 2);
  62
  63   ranges.ResetChecksum();
  64   EXPECT_EQ(289217253u, ranges.checksum());
  65
  66   ranges.set_range(2, 3);
  67   EXPECT_FALSE(ranges.HasValidChecksum());
  68
  69   ranges.ResetChecksum();
  70   EXPECT_EQ(2843835776u, ranges.checksum());
  71   EXPECT_TRUE(ranges.HasValidChecksum());
  72 }
  73
  74 // Table was generated similarly to sample code for CRC-32 given on:
  75 // http://www.w3.org/TR/PNG/#D-CRCAppendix.
  76 TEST(HistogramTest, Crc32TableTest) {
  77   for (int i = 0; i < 256; ++i) {
  78     uint32 checksum = i;
  79     for (int j = 0; j < 8; ++j) {
  80       const uint32 kReversedPolynomial = 0xedb88320L;
  81       if (checksum & 1)
  82         checksum = kReversedPolynomial ^ (checksum >> 1);
  83       else
  84         checksum >>= 1;
  85     }
  86     EXPECT_EQ(kCrcTable[i], checksum);
  87   }
  88 }
  89
  90 }  // namespace
  91 }  // namespace base