Fix variable names and comments in RandGenerator.

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 "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 = 145;
+  const size_t buffer_size = 50;
   char buffer[buffer_size];
   memset(buffer, 0, buffer_size);
   base::RandBytes(buffer, buffer_size);
-  char accumulator = 0;
-  for(size_t i = 0; i < buffer_size; ++i)
-    accumulator |= buffer[i];
-  // In theory this test can fail, but it won't before the universe dies of
-  // heat death.
-  EXPECT_NE(0, accumulator);
+  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(0);
   EXPECT_EQ(0U, 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];
@@ skipping 62 matching lines @@
     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.";
 }