Add integraton test for sync backup/rollback.

sync/test/fake_server/fake_server.cc

 // Copyright 2014 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 "sync/test/fake_server/fake_server.h"
 
 #include <algorithm>
 #include <limits>
 #include <string>
 #include <vector>
@@ skipping 127 matching lines @@
     if (version < min_version)
       min_version = version;
   }
 
   return scoped_ptr<UpdateSieve>(
       new UpdateSieve(request_from_version, min_version));
 }
 
 }  // namespace
 
-FakeServer::FakeServer() : version_(0), store_birthday_(kDefaultStoreBirthday) {
+FakeServer::FakeServer() : version_(0),
+                           store_birthday_(kDefaultStoreBirthday),
+                           error_type_(sync_pb::SyncEnums::SUCCESS) {
   keystore_keys_.push_back(kDefaultKeystoreKey);
   CHECK(CreateDefaultPermanentItems());
 }
 
 FakeServer::~FakeServer() {
   STLDeleteContainerPairSecondPointers(entities_.begin(), entities_.end());
 }
 
 bool FakeServer::CreateDefaultPermanentItems() {
   ModelTypeSet all_types = syncer::ProtocolTypes();
@@ skipping 58 matching lines @@
   sync_pb::ClientToServerMessage message;
   bool parsed = message.ParseFromString(request);
   DCHECK(parsed);
 
   sync_pb::SyncEnums_ErrorType error_code;
   sync_pb::ClientToServerResponse response_proto;
 
   if (message.has_store_birthday() &&
       message.store_birthday() != store_birthday_) {
     error_code = sync_pb::SyncEnums::NOT_MY_BIRTHDAY;
+  } else if (error_type_ != sync_pb::SyncEnums::SUCCESS) {
+    error_code = error_type_;
   } else {
     bool success = false;
     switch (message.message_contents()) {
       case sync_pb::ClientToServerMessage::GET_UPDATES:
         success = HandleGetUpdatesRequest(message.get_updates(),
                                           response_proto.mutable_get_updates());
         break;
       case sync_pb::ClientToServerMessage::COMMIT:
         success = HandleCommitRequest(message.commit(),
                                       message.invalidator_client_id(),
@@ skipping 246 matching lines @@
 }
 
 bool FakeServer::SetNewStoreBirthday(const string& store_birthday) {
   if (store_birthday_ == store_birthday)
     return false;
 
   store_birthday_ = store_birthday;
   return true;
 }
 
+// TODO(pvalenzuela): comments from Richard: we should look at
+// mock_connection_manager.cc and take it as a warning. This style of injecting
+// errors works when there's one or two conditions we care about, but it can
+// eventually lead to a hairball once we have many different conditions and
+// triggering logic.
+void FakeServer::TriggerError(const sync_pb::SyncEnums::ErrorType& error_type) {
+  error_type_ = error_type;
+}
+
 void FakeServer::AddObserver(Observer* observer) {
   observers_.AddObserver(observer);
 }
 
 void FakeServer::RemoveObserver(Observer* observer) {
   observers_.RemoveObserver(observer);
 }
 
 }  // namespace fake_server