Move CachedRanges out and add support for checksum.

base/metrics/bucket_ranges_unittest.cc

Index: base/metrics/bucket_ranges_unittest.cc
===================================================================
--- base/metrics/bucket_ranges_unittest.cc	(revision 0)
+++ base/metrics/bucket_ranges_unittest.cc	(working copy)
@@ -0,0 +1,75 @@
+// Copyright (c) 2012 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.
+
+#include "base/metrics/bucket_ranges.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+namespace {
+
+TEST(BucketRangesTest, NormalSetup) {
+  BucketRanges ranges(5);
+  ASSERT_EQ(5u, ranges.size());
+
+  for (int i = 0; i < 5; i++) {
+    EXPECT_EQ(0, ranges.range(i));
+  }
+  EXPECT_EQ(0u, ranges.checksum());
+
+  ranges.set_range(3, 100);
+  EXPECT_EQ(100, ranges.range(3));
+}
+
+TEST(BucketRangesTest, Equals) {
+  // Compare empty ranges.
+  BucketRanges ranges1(3);
+  BucketRanges ranges2(3);
+  BucketRanges ranges3(5);
+
+  EXPECT_TRUE(ranges1.Equals(&ranges2));
+  EXPECT_FALSE(ranges1.Equals(&ranges3));
+  EXPECT_FALSE(ranges2.Equals(&ranges3));
+
+  // Compare full filled ranges.
+  ranges1.set_range(0, 0);
+  ranges1.set_range(1, 1);
+  ranges1.set_range(2, 2);
+  ranges1.set_checksum(100);
+  ranges2.set_range(0, 0);
+  ranges2.set_range(1, 1);
+  ranges2.set_range(2, 2);
+  ranges2.set_checksum(100);
+
+  EXPECT_TRUE(ranges1.Equals(&ranges2));
+
+  // Checksum does not match.
+  ranges1.set_checksum(99);
+  EXPECT_FALSE(ranges1.Equals(&ranges2));
+  ranges1.set_checksum(100);
+
+  // Range does not match.
+  ranges1.set_range(1, 3);
+  EXPECT_FALSE(ranges1.Equals(&ranges2));
+}
+
+TEST(BucketRangesTest, Checksum) {
+  BucketRanges ranges(3);
+  ranges.set_range(0, 0);
+  ranges.set_range(1, 1);
+  ranges.set_range(2, 2);
+
+  ranges.ResetChecksum();
+  EXPECT_EQ(289217253u, ranges.checksum());
+
+  ranges.set_range(2, 3);
+  EXPECT_FALSE(ranges.HasValidChecksum());
+
+  ranges.ResetChecksum();
+  EXPECT_EQ(2843835776u, ranges.checksum());
+  EXPECT_TRUE(ranges.HasValidChecksum());
+}
+
+}  // namespace
+}  // namespace base