Add 10 minute random fuzz to automatic update check event schedule.

utils_unittest.cc

 // Copyright (c) 2010 The Chromium OS 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 <sys/stat.h>
 #include <sys/types.h>
 #include <errno.h>
+
 #include <string>
 #include <vector>
-#include <gtest/gtest.h>
+
+#include "gtest/gtest.h"
 #include "update_engine/utils.h"
 
 using std::string;
 using std::vector;
 
 namespace chromeos_update_engine {
 
 class UtilsTest : public ::testing::Test { };
 
 TEST(UtilsTest, IsOfficialBuild) {
@@ skipping 129 matching lines @@
 TEST(UtilsTest, IsRemovableDeviceTest) {
   EXPECT_FALSE(utils::IsRemovableDevice(""));
   EXPECT_FALSE(utils::IsRemovableDevice("/dev/non-existent-device"));
 }
 
 TEST(UtilsTest, PartitionNumberTest) {
   EXPECT_EQ("3", utils::PartitionNumber("/dev/sda3"));
   EXPECT_EQ("3", utils::PartitionNumber("/dev/mmc0p3"));
 }
 
-TEST(UtilsTest, ComparePriorities) {
+TEST(UtilsTest, ComparePrioritiesTest) {
   EXPECT_LT(utils::ComparePriorities(utils::kProcessPriorityLow,
                                      utils::kProcessPriorityNormal), 0);
   EXPECT_GT(utils::ComparePriorities(utils::kProcessPriorityNormal,
                                      utils::kProcessPriorityLow), 0);
   EXPECT_EQ(utils::ComparePriorities(utils::kProcessPriorityNormal,
                                      utils::kProcessPriorityNormal), 0);
   EXPECT_GT(utils::ComparePriorities(utils::kProcessPriorityHigh,
                                      utils::kProcessPriorityNormal), 0);
 }
 
+TEST(UtilsTest, FuzzIntTest) {
+  static const unsigned int kRanges[] = { 0, 1, 2, 20 };
+  for (size_t r = 0; r < arraysize(kRanges); ++r) {
+    unsigned int range = kRanges[r];
+    const int kValue = 50;
+    for (int tries = 0; tries < 100; ++tries) {
+      int value = utils::FuzzInt(kValue, range);
+      EXPECT_GE(value, kValue - range / 2);
+      EXPECT_LE(value, kValue + range - range / 2);
+    }
+  }
+}
+
 }  // namespace chromeos_update_engine