Add CompoundSyncable class for synchronizing containers of Syncables.

blimp/helium/compound_syncable_unittest.cc

Index: blimp/helium/compound_syncable_unittest.cc
diff --git a/blimp/helium/compound_syncable_unittest.cc b/blimp/helium/compound_syncable_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..872c8913bb2009b1511a072bb1c47e72984525c2
--- /dev/null
+++ b/blimp/helium/compound_syncable_unittest.cc
@@ -0,0 +1,114 @@
+// 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 "blimp/helium/compound_syncable.h"
+
+#include <string>
+#include <utility>
+
+#include "base/bind.h"
+#include "base/macros.h"
+#include "blimp/helium/lww_register.h"
+#include "blimp/helium/revision_generator.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/protobuf/src/google/protobuf/io/coded_stream.h"
+#include "third_party/protobuf/src/google/protobuf/io/zero_copy_stream_impl_lite.h"
+
+namespace blimp {
+namespace helium {
+namespace {
+
+class SampleCompoundSyncable : public CompoundSyncable {
+ public:
+  explicit SampleCompoundSyncable(Peer bias, Peer running_as)
+      : child1_(
+            CreateAndRegister<LwwRegister<int>>(bias, running_as)),
+        child2_(
+            CreateAndRegister<LwwRegister<int>>(bias, running_as)) {}
+
+  LwwRegister<int>* mutable_child1() { return child1_.get(); }
+  LwwRegister<int>* mutable_child2() { return child2_.get(); }
+
+ private:
+  RegisteredMember<LwwRegister<int>> child1_;
+  RegisteredMember<LwwRegister<int>> child2_;
+
+  DISALLOW_COPY_AND_ASSIGN(SampleCompoundSyncable);
+};
+
+class CompoundSyncableTest : public testing::Test {
+ public:
+  CompoundSyncableTest()
+      : last_sync_engine_(0),
+        engine_(Peer::ENGINE, Peer::ENGINE),
+        client_(Peer::ENGINE, Peer::CLIENT) {}
+
+  ~CompoundSyncableTest() override {}
+
+ protected:
+  // Propagates pending changes from |engine_| to |client_|.
+  void Synchronize() {
+    // Create the changeset stream from |engine_|.
+    std::string changeset;
+    google::protobuf::io::StringOutputStream raw_output_stream(&changeset);
+    google::protobuf::io::CodedOutputStream output_stream(&raw_output_stream);
+
+    engine_.CreateChangesetToCurrent(last_sync_engine_, &output_stream);
+    EXPECT_FALSE(changeset.empty());
+    output_stream.Trim();
+
+    // Apply the changeset stream to |client_|.
+    google::protobuf::io::ArrayInputStream raw_input_stream(changeset.data(),
+                                                            changeset.size());
+    google::protobuf::io::CodedInputStream input_stream(&raw_input_stream);
+
+    last_sync_engine_ = RevisionGenerator::GetInstance()->current();
+    EXPECT_EQ(Result::SUCCESS,
+              client_.ApplyChangeset(last_sync_engine_, &input_stream));
+    engine_.ReleaseBefore(last_sync_engine_);
+
+    // Ensure EOF.
+    EXPECT_FALSE(input_stream.Skip(1));
+  }
+
+  Revision last_sync_engine_ = 0;
+  SampleCompoundSyncable engine_;
+  SampleCompoundSyncable client_;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(CompoundSyncableTest);
+};
+
+TEST_F(CompoundSyncableTest, SequentialMutations) {
+  engine_.mutable_child1()->Set(123);
+  Synchronize();
+  EXPECT_EQ(123, client_.mutable_child1()->Get());
+
+  engine_.mutable_child1()->Set(456);
+  Synchronize();
+  EXPECT_EQ(456, client_.mutable_child1()->Get());
+}
+
+TEST_F(CompoundSyncableTest, MutateMultiple) {
+  engine_.mutable_child1()->Set(123);
+  engine_.mutable_child2()->Set(456);
+  Synchronize();
+  EXPECT_EQ(123, client_.mutable_child1()->Get());
+  EXPECT_EQ(456, client_.mutable_child2()->Get());
+}
+
+TEST_F(CompoundSyncableTest, MutateMultipleDiscrete) {
+  engine_.mutable_child1()->Set(123);
+  Synchronize();
+  EXPECT_EQ(123, client_.mutable_child1()->Get());
+  engine_.mutable_child2()->Set(456);
+  Synchronize();
+  EXPECT_EQ(123, client_.mutable_child1()->Get());
+  EXPECT_EQ(456, client_.mutable_child2()->Get());
+}
+
+}  // namespace
+}  // namespace helium
+}  // namespace blimp