Add a rand_util method for generating a random string.

base/rand_util_unittest.cc

Index: base/rand_util_unittest.cc
===================================================================
--- base/rand_util_unittest.cc	(revision 83409)
+++ base/rand_util_unittest.cc	(working copy)
@@ -1,4 +1,4 @@
-// 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.
 
@@ -22,12 +22,25 @@
 }
 
 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) {