Improve reliability of custom spelling dictionary file.

chrome/browser/spellchecker/spellcheck_custom_dictionary_unittest.cc

Index: chrome/browser/spellchecker/spellcheck_custom_dictionary_unittest.cc
diff --git a/chrome/browser/spellchecker/spellcheck_custom_dictionary_unittest.cc b/chrome/browser/spellchecker/spellcheck_custom_dictionary_unittest.cc
index 1073440e3fa73bf8c75ab05ce0d1493e56f66ebd..30ac46f55270a5ca77e170bae1c2bc6de9488130 100644
--- a/chrome/browser/spellchecker/spellcheck_custom_dictionary_unittest.cc
+++ b/chrome/browser/spellchecker/spellcheck_custom_dictionary_unittest.cc
@@ -4,9 +4,11 @@
 
 #include <vector>
 
+#include "base/file_util.h"
 #include "chrome/browser/spellchecker/spellcheck_custom_dictionary.h"
 #include "chrome/browser/spellchecker/spellcheck_factory.h"
 #include "chrome/browser/spellchecker/spellcheck_service.h"
+#include "chrome/common/chrome_constants.h"
 #include "chrome/common/spellcheck_common.h"
 #include "chrome/test/base/testing_profile.h"
 #include "content/public/test/test_browser_thread.h"
@@ -164,3 +166,68 @@ TEST_F(SpellcheckCustomDictionaryTest, MultiProfile) {
   // TearDown();
   MessageLoop::current()->RunUntilIdle();
 }
+
+TEST_F(SpellcheckCustomDictionaryTest, Reliability) {
+  FilePath dictionary_path(
+      profile_->GetPath().Append(chrome::kCustomDictionaryFileName));
+  SpellcheckService* spellcheck_service =
+      SpellcheckServiceFactory::GetForProfile(profile_.get());
+  SpellcheckCustomDictionary* custom_dictionary =
+      spellcheck_service->GetCustomDictionary();
+  WordList loaded_custom_words;
+  WordList expected;
+  std::string content = "";
+
+  // Legacy empty dictionary should be converted to new format empty dicitonary.
+  content = "";
+  file_util::WriteFile(dictionary_path, content.c_str(), content.length());
+  custom_dictionary->LoadDictionaryIntoCustomWordList(&loaded_custom_words);
+  EXPECT_EQ(loaded_custom_words, expected);
+
+  // Legacy dictionary with two words should be converted to new format
+  // dictionary with two words.
+  content = "foo\nbar\n";
+  file_util::WriteFile(dictionary_path, content.c_str(), content.length());
+  custom_dictionary->LoadDictionaryIntoCustomWordList(&loaded_custom_words);
+  expected.push_back("bar");
+  expected.push_back("foo");
+  EXPECT_EQ(expected, loaded_custom_words);
+
+  // Write to dicitonary should backup previous version and write the word to
+  // the end of the dictionary. The dicitonary is now unsorted.
+  custom_dictionary->WriteWordToCustomDictionary("baz");
+
+  // Reloading the custom dicitonary will backup the unsorted version of the
+  // dictionary and write a sorted version to disk as part of the cleanup that
+  // happens on load.
+  custom_dictionary->LoadDictionaryIntoCustomWordList(&loaded_custom_words);
+  expected.insert(expected.begin() + 1, "baz");
+  EXPECT_EQ(expected, loaded_custom_words);
+
+  // If the dictionary file is corrupted on disk, the previous version should be
+  // reloaded. The previous version is unsorted. The load process sorts it as
+  // part of cleanup.
+  content.clear();
+  file_util::ReadFileToString(dictionary_path, &content);
+  content.append("corruption");
+  file_util::WriteFile(dictionary_path, content.c_str(), content.length());
+  custom_dictionary->LoadDictionaryIntoCustomWordList(&loaded_custom_words);
+  EXPECT_EQ(expected, loaded_custom_words);
+
+  // Write "fun" successfully, but corrupt the write of "zoo". Reloading the
+  // dicitonary should undo the "zoo" write and see only "fun" word at the end.
+  custom_dictionary->WriteWordToCustomDictionary("fun");
+  custom_dictionary->WriteWordToCustomDictionary("zoo");
+  content.clear();
+  file_util::ReadFileToString(dictionary_path, &content);
+  content.append("corruption");
+  file_util::WriteFile(dictionary_path, content.c_str(), content.length());
+  custom_dictionary->LoadDictionaryIntoCustomWordList(&loaded_custom_words);
+  expected.push_back("fun");
+  // The write of "zoo" was corrupted, so not expecting to see it.
+  EXPECT_EQ(expected, loaded_custom_words);
+
+  // Flush the loop now to prevent service init tasks from being run during
+  // TearDown();
+  MessageLoop::current()->RunUntilIdle();
+}