Add a rand_util method for generating a random string.

base/rand_util_unittest.cc

-// Copyright (c) 2008 The Chromium Authors. All rights reserved.
+// 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 <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);
+  // 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, RandString) {
+  std::string random_string = base::RandString(0);
+  EXPECT_EQ(0U, random_string.size());
+  random_string = base::RandString(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());
 }