Move base to DEPS

base/rand_util_unittest.cc

-// Copyright (c) 2011 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/rand_util.h"
-
-#include <algorithm>
-#include <limits>
-
-#include "base/logging.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/time/time.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
-namespace {
-
-const int kIntMin = std::numeric_limits<int>::min();
-const int kIntMax = std::numeric_limits<int>::max();
-
-}  // namespace
-
-TEST(RandUtilTest, SameMinAndMax) {
-  EXPECT_EQ(base::RandInt(0, 0), 0);
-  EXPECT_EQ(base::RandInt(kIntMin, kIntMin), kIntMin);
-  EXPECT_EQ(base::RandInt(kIntMax, kIntMax), kIntMax);
-}
-
-TEST(RandUtilTest, RandDouble) {
-  // Force 64-bit precision, making sure we're not in a 80-bit FPU register.
-  volatile double number = base::RandDouble();
-  EXPECT_GT(1.0, number);
-  EXPECT_LE(0.0, number);
-}
-
-TEST(RandUtilTest, RandBytes) {
-  const size_t buffer_size = 50;
-  char buffer[buffer_size];
-  memset(buffer, 0, buffer_size);
-  base::RandBytes(buffer, buffer_size);
-  std::sort(buffer, buffer + buffer_size);
-  // Probability of occurrence of less than 25 unique bytes in 50 random bytes
-  // is below 10^-25.
-  EXPECT_GT(std::unique(buffer, buffer + buffer_size) - buffer, 25);
-}
-
-TEST(RandUtilTest, RandBytesAsString) {
-  std::string random_string = base::RandBytesAsString(1);
-  EXPECT_EQ(1U, random_string.size());
-  random_string = base::RandBytesAsString(145);
-  EXPECT_EQ(145U, random_string.size());
-  char accumulator = 0;
-  for (size_t i = 0; i < random_string.size(); ++i)
-    accumulator |= random_string[i];
-  // In theory this test can fail, but it won't before the universe dies of
-  // heat death.
-  EXPECT_NE(0, accumulator);
-}
-
-// Make sure that it is still appropriate to use RandGenerator in conjunction
-// with std::random_shuffle().
-TEST(RandUtilTest, RandGeneratorForRandomShuffle) {
-  EXPECT_EQ(base::RandGenerator(1), 0U);
-  EXPECT_LE(std::numeric_limits<ptrdiff_t>::max(),
-            std::numeric_limits<int64>::max());
-}
-
-TEST(RandUtilTest, RandGeneratorIsUniform) {
-  // Verify that RandGenerator has a uniform distribution. This is a
-  // regression test that consistently failed when RandGenerator was
-  // implemented this way:
-  //
-  //   return base::RandUint64() % max;
-  //
-  // A degenerate case for such an implementation is e.g. a top of
-  // range that is 2/3rds of the way to MAX_UINT64, in which case the
-  // bottom half of the range would be twice as likely to occur as the
-  // top half. A bit of calculus care of jar@ shows that the largest
-  // measurable delta is when the top of the range is 3/4ths of the
-  // way, so that's what we use in the test.
-  const uint64 kTopOfRange = (std::numeric_limits<uint64>::max() / 4ULL) * 3ULL;
-  const uint64 kExpectedAverage = kTopOfRange / 2ULL;
-  const uint64 kAllowedVariance = kExpectedAverage / 50ULL;  // +/- 2%
-  const int kMinAttempts = 1000;
-  const int kMaxAttempts = 1000000;
-
-  double cumulative_average = 0.0;
-  int count = 0;
-  while (count < kMaxAttempts) {
-    uint64 value = base::RandGenerator(kTopOfRange);
-    cumulative_average = (count * cumulative_average + value) / (count + 1);
-
-    // Don't quit too quickly for things to start converging, or we may have
-    // a false positive.
-    if (count > kMinAttempts &&
-        kExpectedAverage - kAllowedVariance < cumulative_average &&
-        cumulative_average < kExpectedAverage + kAllowedVariance) {
-      break;
-    }
-
-    ++count;
-  }
-
-  ASSERT_LT(count, kMaxAttempts) << "Expected average was " <<
-      kExpectedAverage << ", average ended at " << cumulative_average;
-}
-
-TEST(RandUtilTest, RandUint64ProducesBothValuesOfAllBits) {
-  // This tests to see that our underlying random generator is good
-  // enough, for some value of good enough.
-  uint64 kAllZeros = 0ULL;
-  uint64 kAllOnes = ~kAllZeros;
-  uint64 found_ones = kAllZeros;
-  uint64 found_zeros = kAllOnes;
-
-  for (size_t i = 0; i < 1000; ++i) {
-    uint64 value = base::RandUint64();
-    found_ones |= value;
-    found_zeros &= value;
-
-    if (found_zeros == kAllZeros && found_ones == kAllOnes)
-      return;
-  }
-
-  FAIL() << "Didn't achieve all bit values in maximum number of tries.";
-}
-
-// Benchmark test for RandBytes().  Disabled since it's intentionally slow and
-// does not test anything that isn't already tested by the existing RandBytes()
-// tests.
-TEST(RandUtilTest, DISABLED_RandBytesPerf) {
-  // Benchmark the performance of |kTestIterations| of RandBytes() using a
-  // buffer size of |kTestBufferSize|.
-  const int kTestIterations = 10;
-  const size_t kTestBufferSize = 1 * 1024 * 1024;
-
-  scoped_ptr<uint8[]> buffer(new uint8[kTestBufferSize]);
-  const base::TimeTicks now = base::TimeTicks::Now();
-  for (int i = 0; i < kTestIterations; ++i)
-    base::RandBytes(buffer.get(), kTestBufferSize);
-  const base::TimeTicks end = base::TimeTicks::Now();
-
-  LOG(INFO) << "RandBytes(" << kTestBufferSize << ") took: "
-            << (end - now).InMicroseconds() << "µs";
-}