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   ASSERT_EQ(4u, ranges.bucket_count());
  16
  17   for (int i = 0; i < 5; ++i) {
  18     EXPECT_EQ(0, ranges.range(i));
  19   }
  20   EXPECT_EQ(0u, ranges.checksum());
  21
  22   ranges.set_range(3, 100);
  23   EXPECT_EQ(100, ranges.range(3));
  24 }
  25
  26 TEST(BucketRangesTest, Equals) {
  27   // Compare empty ranges.
  28   BucketRanges ranges1(3);
  29   BucketRanges ranges2(3);
  30   BucketRanges ranges3(5);
  31
  32   EXPECT_TRUE(ranges1.Equals(&ranges2));
  33   EXPECT_FALSE(ranges1.Equals(&ranges3));
  34   EXPECT_FALSE(ranges2.Equals(&ranges3));
  35
  36   // Compare full filled ranges.
  37   ranges1.set_range(0, 0);
  38   ranges1.set_range(1, 1);
  39   ranges1.set_range(2, 2);
  40   ranges1.set_checksum(100);
  41   ranges2.set_range(0, 0);
  42   ranges2.set_range(1, 1);
  43   ranges2.set_range(2, 2);
  44   ranges2.set_checksum(100);
  45
  46   EXPECT_TRUE(ranges1.Equals(&ranges2));
  47
  48   // Checksum does not match.
  49   ranges1.set_checksum(99);
  50   EXPECT_FALSE(ranges1.Equals(&ranges2));
  51   ranges1.set_checksum(100);
  52
  53   // Range does not match.
  54   ranges1.set_range(1, 3);
  55   EXPECT_FALSE(ranges1.Equals(&ranges2));
  56 }
  57
  58 TEST(BucketRangesTest, Checksum) {
  59   BucketRanges ranges(3);
  60   ranges.set_range(0, 0);
  61   ranges.set_range(1, 1);
  62   ranges.set_range(2, 2);
  63
  64   ranges.ResetChecksum();
  65   EXPECT_EQ(289217253u, ranges.checksum());
  66
  67   ranges.set_range(2, 3);
  68   EXPECT_FALSE(ranges.HasValidChecksum());
  69
  70   ranges.ResetChecksum();
  71   EXPECT_EQ(2843835776u, ranges.checksum());
  72   EXPECT_TRUE(ranges.HasValidChecksum());
  73 }
  74
  75 // Table was generated similarly to sample code for CRC-32 given on:
  76 // http://www.w3.org/TR/PNG/#D-CRCAppendix.
  77 TEST(BucketRangesTest, Crc32TableTest) {
  78   for (int i = 0; i < 256; ++i) {
  79     uint32 checksum = i;
  80     for (int j = 0; j < 8; ++j) {
  81       const uint32 kReversedPolynomial = 0xedb88320L;
  82       if (checksum & 1)
  83         checksum = kReversedPolynomial ^ (checksum >> 1);
  84       else
  85         checksum >>= 1;
  86     }
  87     EXPECT_EQ(kCrcTable[i], checksum);
  88   }
  89 }
  90
  91 }  // namespace
  92 }  // namespace base