Add a unit test for JsonPrefStore::Remove.

base/prefs/json_pref_store_unittest.cc

Index: base/prefs/json_pref_store_unittest.cc
diff --git a/base/prefs/json_pref_store_unittest.cc b/base/prefs/json_pref_store_unittest.cc
index 119a29cd96c94eede7e15a9a81c14f3db3dcdfa0..ebc67fb79016482718fc626b71685df5a230bd62 100644
--- a/base/prefs/json_pref_store_unittest.cc
+++ b/base/prefs/json_pref_store_unittest.cc
@@ -257,6 +257,29 @@ TEST_F(JsonPrefStoreTest, PreserveEmptyValues) {
   EXPECT_TRUE(DictionaryValue().Equals(result));
 }
 
+TEST_F(JsonPrefStoreTest, Remove) {
+  ASSERT_TRUE(base::CopyFile(data_dir_.AppendASCII("remove.original.json"),
+                             temp_dir_.path().AppendASCII("remove.json")));
+  base::FilePath input_output_file =
+      temp_dir_.path().AppendASCII("remove.json");
+  ASSERT_TRUE(PathExists(input_output_file));
+  scoped_refptr<JsonPrefStore> pref_store = new JsonPrefStore(
+      input_output_file,
+      message_loop_.message_loop_proxy().get(),
+      scoped_ptr<PrefFilter>());
+  ASSERT_EQ(PersistentPrefStore::PREF_READ_ERROR_NONE, pref_store->ReadPrefs());
+  ASSERT_FALSE(pref_store->ReadOnly());

[Mattias Nissler (ping if slow), 2014/01/23 09:07:54]

Reading this code, I have no idea what the test is supposed to test, can you
improve that?

This would be much clearer if you just constructed the input data
programmatically instead of separating it out into a file and reading it from
there. Another option could be to put a comment here that puts the reader on the
right track.

+
+  pref_store->RemoveValue("long_int.pref");
+
+  pref_store->CommitPendingWrite();
+  RunLoop().RunUntilIdle();
+
+  base::FilePath golden_output_file =
+      data_dir_.AppendASCII("remove.golden.json");
+  EXPECT_TRUE(TextContentsEqual(golden_output_file, input_output_file));
+}
+
 // Tests asynchronous reading of the file when there is no file.
 TEST_F(JsonPrefStoreTest, AsyncNonExistingFile) {
   base::FilePath bogus_input_file = data_dir_.AppendASCII("read.txt");