AppendToFile implementation.

base/file_util_unittest.cc

 // Copyright (c) 2012 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 "build/build_config.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #include <shellapi.h>
 #include <shlobj.h>
@@ skipping 1772 matching lines @@
   EXPECT_TRUE(c5.HasFile(dir2innerfile));
   EXPECT_EQ(c5.size(), 5);
 
   // Make sure the destructor closes the find handle while in the middle of a
   // query to allow TearDown to delete the directory.
   file_util::FileEnumerator f6(temp_dir_.path(), true, FILES_AND_DIRECTORIES);
   EXPECT_FALSE(f6.Next().value().empty());  // Should have found something
                                             // (we don't care what).
 }
 
+TEST_F(FileUtilTest, AppendToFile) {
+  FilePath data_dir =
+      temp_dir_.path().Append(FILE_PATH_LITERAL("FilePathTest"));
+
+  // Create a fresh, empty copy of this directory.
+  if (file_util::PathExists(data_dir)) {
+    ASSERT_TRUE(file_util::Delete(data_dir, true));
+  }
+  ASSERT_TRUE(file_util::CreateDirectory(data_dir));
+
+  // Create a fresh, empty copy of this directory.
+  if (file_util::PathExists(data_dir)) {
+    ASSERT_TRUE(file_util::Delete(data_dir, true));
+  }
+  ASSERT_TRUE(file_util::CreateDirectory(data_dir));
+  FilePath foobar(data_dir.Append(FILE_PATH_LITERAL("foobar.txt")));
+
+  std::string data("hello");
+  EXPECT_EQ(-1, file_util::AppendToFile(foobar, data.c_str(), data.length()));
+  EXPECT_EQ(static_cast<int>(data.length()),
+            file_util::WriteFile(foobar, data.c_str(), data.length()));
+  EXPECT_EQ(static_cast<int>(data.length()),
+            file_util::AppendToFile(foobar, data.c_str(), data.length()));
+
+  const std::wstring read_content = ReadTextFile(foobar);
+  EXPECT_EQ(L"hellohello", read_content);
+}
+
 TEST_F(FileUtilTest, Contains) {
   FilePath data_dir =
       temp_dir_.path().Append(FILE_PATH_LITERAL("FilePathTest"));
 
   // Create a fresh, empty copy of this directory.
   if (file_util::PathExists(data_dir)) {
     ASSERT_TRUE(file_util::Delete(data_dir, true));
   }
   ASSERT_TRUE(file_util::CreateDirectory(data_dir));
 
@@ skipping 445 matching lines @@
       file_util::VerifyPathControlledByUser(
           base_dir_, text_file_, uid_, ok_gids_));
   EXPECT_TRUE(
       file_util::VerifyPathControlledByUser(
           sub_dir_, text_file_, uid_, ok_gids_));
 }
 
 #endif  // defined(OS_POSIX)
 
 }  // namespace