Support zero-sized values.

base/debug/activity_tracker_unittest.cc

 // Copyright 2016 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/debug/activity_tracker.h"
 
 #include <memory>
 
 #include "base/bind.h"
 #include "base/files/file.h"
@@ skipping 73 matching lines @@
     return GlobalActivityTracker::Get()->user_data_allocator_.cache_used();
   }
 
   static void DoNothing() {}
 };
 
 TEST_F(ActivityTrackerTest, UserDataTest) {
   char buffer[256];
   memset(buffer, 0, sizeof(buffer));
   ActivityUserData data(buffer, sizeof(buffer));
-  ASSERT_EQ(sizeof(buffer) - 8, data.available_);
+  const size_t space = sizeof(buffer) - 8;
+  ASSERT_EQ(space, data.available_);
 
   data.SetInt("foo", 1);
-  ASSERT_EQ(sizeof(buffer) - 8 - 24, data.available_);
+  ASSERT_EQ(space - 24, data.available_);
 
   data.SetUint("b", 1U);  // Small names fit beside header in a word.
-  ASSERT_EQ(sizeof(buffer) - 8 - 24 - 16, data.available_);
+  ASSERT_EQ(space - 24 - 16, data.available_);
 
   data.Set("c", buffer, 10);
-  ASSERT_EQ(sizeof(buffer) - 8 - 24 - 16 - 24, data.available_);
+  ASSERT_EQ(space - 24 - 16 - 24, data.available_);
 
   data.SetString("dear john", "it's been fun");
-  ASSERT_EQ(sizeof(buffer) - 8 - 24 - 16 - 24 - 32, data.available_);
+  ASSERT_EQ(space - 24 - 16 - 24 - 32, data.available_);
 
   data.Set("c", buffer, 20);
-  ASSERT_EQ(sizeof(buffer) - 8 - 24 - 16 - 24 - 32, data.available_);
+  ASSERT_EQ(space - 24 - 16 - 24 - 32, data.available_);
 
   data.SetString("dear john", "but we're done together");
-  ASSERT_EQ(sizeof(buffer) - 8 - 24 - 16 - 24 - 32, data.available_);
+  ASSERT_EQ(space - 24 - 16 - 24 - 32, data.available_);
 
   data.SetString("dear john", "bye");
-  ASSERT_EQ(sizeof(buffer) - 8 - 24 - 16 - 24 - 32, data.available_);
+  ASSERT_EQ(space - 24 - 16 - 24 - 32, data.available_);
 
   data.SetChar("d", 'x');
-  ASSERT_EQ(sizeof(buffer) - 8 - 24 - 16 - 24 - 32 - 8, data.available_);
+  ASSERT_EQ(space - 24 - 16 - 24 - 32 - 8, data.available_);
 
   data.SetBool("ee", true);
-  ASSERT_EQ(sizeof(buffer) - 8 - 24 - 16 - 24 - 32 - 8 - 16, data.available_);
+  ASSERT_EQ(space - 24 - 16 - 24 - 32 - 8 - 16, data.available_);
+
+  data.SetString("f", "");
+  ASSERT_EQ(space - 24 - 16 - 24 - 32 - 8 - 16 - 8, data.available_);
 }
 
 TEST_F(ActivityTrackerTest, PushPopTest) {
   std::unique_ptr<ThreadActivityTracker> tracker = CreateActivityTracker();
   ThreadActivityTracker::Snapshot snapshot;
 
   ASSERT_TRUE(tracker->CreateSnapshot(&snapshot));
   ASSERT_EQ(0U, snapshot.activity_stack_depth);
   ASSERT_EQ(0U, snapshot.activity_stack.size());
 
@@ skipping 195 matching lines @@
   EXPECT_EQ(starting_inactive, GetGlobalInactiveTrackerCount());
 
   t2.Exit();
   t2.Join();
   EXPECT_EQ(starting_active, GetGlobalActiveTrackerCount());
   EXPECT_EQ(starting_inactive + 1, GetGlobalInactiveTrackerCount());
 }
 
 }  // namespace debug
 }  // namespace base