[Sync] Adding a passthrough MetadataChangeList implementation.

components/sync/model_impl/passthrough_metadata_change_list_unittest.cc

Index: components/sync/model_impl/passthrough_metadata_change_list_unittest.cc
diff --git a/components/sync/model_impl/passthrough_metadata_change_list_unittest.cc b/components/sync/model_impl/passthrough_metadata_change_list_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..ca5c6a44f06c8ee51e796160aec8e447fd676447
--- /dev/null
+++ b/components/sync/model_impl/passthrough_metadata_change_list_unittest.cc
@@ -0,0 +1,180 @@
+// 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 "components/sync/model_impl/passthrough_metadata_change_list.h"
+
+#include <iterator>
+#include <map>
+#include <memory>
+#include <set>
+#include <utility>
+#include <vector>
+
+#include "base/bind.h"
+#include "base/run_loop.h"
+#include "components/sync/model/mock_model_type_store.h"
+#include "components/sync/protocol/entity_metadata.pb.h"
+#include "components/sync/protocol/model_type_state.pb.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace syncer {
+
+namespace {
+
+using EntityMetadata = sync_pb::EntityMetadata;
+using ModelTypeState = sync_pb::ModelTypeState;
+using WriteBatch = ModelTypeStore::WriteBatch;
+
+const char kKey1[] = "key1";
+const char kKey2[] = "key2";
+
+void RecordWriteGlobalMetadata(std::vector<std::string>* vector,
+                               WriteBatch* batch,
+                               const std::string& value) {
+  vector->push_back(value);
+}
+
+void RecordDeleteGlobalMetadata(int* call_count, WriteBatch* batch) {
+  ++(*call_count);
+}
+
+void RecordWriteMetadata(std::multimap<std::string, std::string>* map,
+                         WriteBatch* batch,
+                         const std::string& key,
+                         const std::string& value) {
+  map->insert(std::make_pair(key, value));
+}
+
+void RecordDeleteMetadata(std::multiset<std::string>* set,
+                          WriteBatch* batch,
+                          const std::string& id) {
+  set->insert(id);
+}
+
+}  // namespace
+
+class PassthroughMetadataChangeListTest : public testing::Test {
+ protected:
+  PassthroughMetadataChangeListTest()
+      : batch_(store_.CreateWriteBatch()), passthrough_(&store_, batch_.get()) {
+    store_.RegisterWriteGlobalMetadataHandler(
+        base::Bind(&RecordWriteGlobalMetadata, &global_metadata_vector_));
+    store_.RegisterDeleteGlobalMetadataHandler(
+        base::Bind(&RecordDeleteGlobalMetadata, &clear_global_metadata_count_));
+    store_.RegisterWriteMetadataHandler(
+        base::Bind(&RecordWriteMetadata, &update_metadata_map_));
+    store_.RegisterDeleteMetadataHandler(
+        base::Bind(&RecordDeleteMetadata, &clear_metadata_set_));
+  }
+
+  MetadataChangeList* mcl() { return &passthrough_; }
+  const std::vector<std::string>& global_metadata_vector() {
+    return global_metadata_vector_;
+  }
+  int clear_global_metadata_count() { return clear_global_metadata_count_; }
+  const std::multimap<std::string, std::string>& update_metadata_map() {
+    return update_metadata_map_;
+  }
+  const std::multiset<std::string>& clear_metadata_set() {
+    return clear_metadata_set_;
+  }
+
+ private:
+  // MockModelTypeStore needs MessageLoop.
+  base::MessageLoop message_loop_;
+
+  MockModelTypeStore store_;
+  std::unique_ptr<WriteBatch> batch_;
+  PassthroughMetadataChangeList passthrough_;
+
+  std::vector<std::string> global_metadata_vector_;
+  int clear_global_metadata_count_ = 0;
+  std::multimap<std::string, std::string> update_metadata_map_;
+  std::multiset<std::string> clear_metadata_set_;
+};
+
+TEST_F(PassthroughMetadataChangeListTest, ConstructorOnly) {
+  EXPECT_EQ(0u, global_metadata_vector().size());
+  EXPECT_EQ(0, clear_global_metadata_count());
+  EXPECT_EQ(0u, update_metadata_map().size());
+  EXPECT_EQ(0u, clear_metadata_set().size());
+}
+
+TEST_F(PassthroughMetadataChangeListTest, UpdateModelTypeState) {
+  ModelTypeState state;
+  mcl()->UpdateModelTypeState(state);
+  EXPECT_EQ(1u, global_metadata_vector().size());
+  EXPECT_EQ(0, clear_global_metadata_count());
+  EXPECT_EQ(0u, update_metadata_map().size());
+  EXPECT_EQ(0u, clear_metadata_set().size());
+  EXPECT_EQ(state.SerializeAsString(), global_metadata_vector()[0]);
+
+  state.set_encryption_key_name("ekn");
+  EXPECT_NE(state.SerializeAsString(), global_metadata_vector()[0]);
+  mcl()->UpdateModelTypeState(state);
+  EXPECT_EQ(2u, global_metadata_vector().size());
+  EXPECT_EQ(state.SerializeAsString(), global_metadata_vector()[1]);
+}
+
+TEST_F(PassthroughMetadataChangeListTest, ClearModelTypeState) {
+  mcl()->ClearModelTypeState();
+  EXPECT_EQ(0u, global_metadata_vector().size());
+  EXPECT_EQ(1, clear_global_metadata_count());
+  EXPECT_EQ(0u, update_metadata_map().size());
+  EXPECT_EQ(0u, clear_metadata_set().size());
+
+  mcl()->ClearModelTypeState();
+  EXPECT_EQ(2, clear_global_metadata_count());
+}
+
+TEST_F(PassthroughMetadataChangeListTest, UpdateMetadata) {
+  EntityMetadata metadata;
+  metadata.set_client_tag_hash("some_hash");
+  mcl()->UpdateMetadata(kKey1, metadata);
+  EXPECT_EQ(0u, global_metadata_vector().size());
+  EXPECT_EQ(0, clear_global_metadata_count());
+  EXPECT_EQ(1u, update_metadata_map().size());
+  EXPECT_EQ(1u, update_metadata_map().count(kKey1));
+  EXPECT_EQ(update_metadata_map().find(kKey1)->second,
+            metadata.SerializeAsString());
+  EXPECT_EQ(0u, clear_metadata_set().size());
+
+  metadata.set_client_tag_hash("other_hash");
+  mcl()->UpdateMetadata(kKey1, metadata);
+  mcl()->UpdateMetadata(kKey2, metadata);
+  EXPECT_EQ(3u, update_metadata_map().size());
+  EXPECT_EQ(2u, update_metadata_map().count(kKey1));
+  EXPECT_EQ(1u, update_metadata_map().count(kKey2));
+  EXPECT_NE(update_metadata_map().find(kKey1)->second,

[maxbogue, 2016/11/02 22:53:30]

would probably be easier to parse this and the next one if you did like...

auto key1_iter = update_metadata_map().find(kKey1);

on a preceding line. Also if you made metadata1 and metadata2 separate, you
could EXPECT_EQ(metadata1.SerializeAsString(), ...)

[skym, 2016/11/02 23:10:56]

Done and Done.

+            metadata.SerializeAsString());
+  EXPECT_EQ(std::next(update_metadata_map().find(kKey1))->second,

[maxbogue, 2016/11/02 22:53:30]

expected thing first! here and above and below.

[skym, 2016/11/02 23:10:56]

Done.

+            metadata.SerializeAsString());
+  EXPECT_EQ(update_metadata_map().find(kKey2)->second,
+            metadata.SerializeAsString());
+}
+
+TEST_F(PassthroughMetadataChangeListTest, ClearMetadata) {
+  mcl()->ClearMetadata(kKey1);
+  EXPECT_EQ(1u, clear_metadata_set().size());
+  EXPECT_EQ(1u, clear_metadata_set().count(kKey1));
+
+  mcl()->ClearMetadata(kKey1);
+  mcl()->ClearMetadata(kKey2);
+  EXPECT_EQ(3u, clear_metadata_set().size());
+  EXPECT_EQ(2u, clear_metadata_set().count(kKey1));
+  EXPECT_EQ(1u, clear_metadata_set().count(kKey2));
+}
+
+TEST_F(PassthroughMetadataChangeListTest, Everything) {
+  mcl()->UpdateModelTypeState(ModelTypeState());
+  mcl()->ClearModelTypeState();
+  mcl()->UpdateMetadata(kKey1, EntityMetadata());
+  mcl()->ClearMetadata(kKey1);
+  EXPECT_EQ(1u, global_metadata_vector().size());
+  EXPECT_EQ(1, clear_global_metadata_count());
+  EXPECT_EQ(1u, update_metadata_map().size());
+  EXPECT_EQ(1u, clear_metadata_set().size());
+}
+
+}  // namespace syncer