[Sync] Add a sanity integration test for USS.

chrome/browser/sync/test/integration/two_client_uss_sync_test.cc

Index: chrome/browser/sync/test/integration/two_client_uss_sync_test.cc
diff --git a/chrome/browser/sync/test/integration/two_client_uss_sync_test.cc b/chrome/browser/sync/test/integration/two_client_uss_sync_test.cc
new file mode 100644
index 0000000000000000000000000000000000000000..6ddd813469007c867d6edb3d85f179e87b0b35e4
--- /dev/null
+++ b/chrome/browser/sync/test/integration/two_client_uss_sync_test.cc
@@ -0,0 +1,195 @@
+// 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 "base/macros.h"
+#include "base/memory/ptr_util.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "chrome/browser/sync/chrome_sync_client.h"
+#include "chrome/browser/sync/profile_sync_service_factory.h"
+#include "chrome/browser/sync/test/integration/profile_sync_service_harness.h"
+#include "chrome/browser/sync/test/integration/status_change_checker.h"
+#include "chrome/browser/sync/test/integration/sync_integration_test_util.h"
+#include "chrome/browser/sync/test/integration/sync_test.h"
+#include "components/browser_sync/browser/profile_sync_components_factory_impl.h"
+#include "components/sync/api/fake_model_type_service.h"
+
+using browser_sync::ChromeSyncClient;
+using syncer_v2::FakeModelTypeService;
+using syncer_v2::ModelTypeService;
+using syncer_v2::SharedModelTypeProcessor;
+
+// A ChromeSyncClient that provides a ModelTypeService for PREFERENCES.
+class TestSyncClient : public ChromeSyncClient {
+ public:
+  TestSyncClient(Profile* profile, ModelTypeService* service)
+      : ChromeSyncClient(profile), service_(service) {}
+
+  base::WeakPtr<ModelTypeService> GetModelTypeServiceForType(
+      syncer::ModelType type) override {
+    return type == syncer::PREFERENCES
+               ? service_->AsWeakPtr()
+               : ChromeSyncClient::GetModelTypeServiceForType(type);
+  }
+
+ private:
+  ModelTypeService* const service_;
+};
+
+// A FakeModelTypeService that supports observing ApplySyncChanges.
+class TestModelTypeService : public FakeModelTypeService {
+ public:
+  class Observer {
+   public:
+    virtual void OnApplySyncChanges() = 0;
+  };
+
+  TestModelTypeService()
+      : FakeModelTypeService(
+            base::Bind(&SharedModelTypeProcessor::CreateAsChangeProcessor)) {}
+
+  syncer::SyncError ApplySyncChanges(
+      std::unique_ptr<syncer_v2::MetadataChangeList> metadata_changes,
+      syncer_v2::EntityChangeList entity_changes) override {
+    syncer::SyncError error = FakeModelTypeService::ApplySyncChanges(
+        std::move(metadata_changes), entity_changes);
+    NotifyObservers();
+    return error;
+  }
+
+  void OnChangeProcessorSet() override {
+    change_processor()->OnMetadataLoaded(syncer::SyncError(),
+                                         db().CreateMetadataBatch());
+  }
+
+  void AddObserver(Observer* observer) { observers_.insert(observer); }
+  void RemoveObserver(Observer* observer) { observers_.erase(observer); }
+
+ private:
+  void NotifyObservers() {
+    for (Observer* observer : observers_) {
+      observer->OnApplySyncChanges();
+    }
+  }
+
+  std::set<Observer*> observers_;
+};
+
+// A StatusChangeChecker for checking the status of keys in a
+// TestModelTypeService::Store.
+class KeyChecker : public StatusChangeChecker,
+                   public TestModelTypeService::Observer {
+ public:
+  KeyChecker(TestModelTypeService* service, const std::string& key)
+      : service_(service), key_(key) {}
+  ~KeyChecker() override {}
+
+  void OnApplySyncChanges() override { CheckExitCondition(); }
+
+  bool Wait() {
+    if (IsExitConditionSatisfied()) {
+      DVLOG(1) << "Wait() -> Exit before waiting: " << GetDebugMessage();
+      return true;
+    }
+
+    service_->AddObserver(this);
+    StartBlockingWait();
+    service_->RemoveObserver(this);
+    return !TimedOut();
+  }
+
+ protected:
+  TestModelTypeService* const service_;
+  const std::string key_;
+};
+
+// Wait for a key to be present.
+class KeyPresentChecker : public KeyChecker {
+ public:
+  KeyPresentChecker(TestModelTypeService* service, const std::string& key)
+      : KeyChecker(service, key) {}
+  ~KeyPresentChecker() override {}
+
+  bool IsExitConditionSatisfied() override {
+    return service_->db().HasData(key_);
+  }
+
+  std::string GetDebugMessage() const override {
+    return "Waiting for key '" + key_ + "' to be present.";
+  }
+};
+
+// Wait for a key to be absent.
+class KeyAbsentChecker : public KeyChecker {
+ public:
+  KeyAbsentChecker(TestModelTypeService* service, const std::string& key)
+      : KeyChecker(service, key) {}
+  ~KeyAbsentChecker() override {}
+
+  bool IsExitConditionSatisfied() override {
+    return !service_->db().HasData(key_);
+  }
+
+  std::string GetDebugMessage() const override {
+    return "Waiting for key '" + key_ + "' to be absent.";
+  }
+};
+
+class TwoClientUssSyncTest : public SyncTest {
+ public:
+  TwoClientUssSyncTest() : SyncTest(TWO_CLIENT) {
+    DisableVerifier();
+    sync_client_factory_ = base::Bind(&TwoClientUssSyncTest::CreateSyncClient,
+                                      base::Unretained(this));
+    ProfileSyncServiceFactory::SetSyncClientFactoryForTest(
+        &sync_client_factory_);
+    ProfileSyncComponentsFactoryImpl::OverridePrefsForUssTest(true);
+  }
+
+  ~TwoClientUssSyncTest() override {
+    ProfileSyncServiceFactory::SetSyncClientFactoryForTest(nullptr);
+    ProfileSyncComponentsFactoryImpl::OverridePrefsForUssTest(false);
+  }
+
+  bool TestUsesSelfNotifications() override { return false; }
+
+  TestModelTypeService* GetModelTypeService(int i) {
+    return services_.at(i).get();
+  }
+
+ protected:
+  std::unique_ptr<sync_driver::SyncClient> CreateSyncClient(Profile* profile) {
+    if (!first_client_ignored_) {
+      // The test infra creates a profile before the two made for sync tests.
+      first_client_ignored_ = true;
+      return base::MakeUnique<ChromeSyncClient>(profile);
+    }
+    auto service = base::MakeUnique<TestModelTypeService>();
+    auto client = base::MakeUnique<TestSyncClient>(profile, service.get());
+    clients_.push_back(client.get());
+    services_.push_back(std::move(service));
+    return std::move(client);
+  }
+
+  ProfileSyncServiceFactory::SyncClientFactory sync_client_factory_;
+  std::vector<std::unique_ptr<TestModelTypeService>> services_;
+  std::vector<TestSyncClient*> clients_;
+  bool first_client_ignored_ = false;
+
+  DISALLOW_COPY_AND_ASSIGN(TwoClientUssSyncTest);
+};
+
+IN_PROC_BROWSER_TEST_F(TwoClientUssSyncTest, Sanity) {
+  ASSERT_TRUE(SetupSync());
+  ASSERT_EQ(2U, clients_.size());
+  ASSERT_EQ(2U, services_.size());
+  TestModelTypeService* model1 = GetModelTypeService(0);
+  TestModelTypeService* model2 = GetModelTypeService(1);
+
+  model1->WriteItem("foo", "bar");
+  ASSERT_TRUE(KeyPresentChecker(model2, "foo").Wait());
+  EXPECT_EQ("bar", model2->db().GetValue("foo"));
+
+  model1->DeleteItem("foo");
+  ASSERT_TRUE(KeyAbsentChecker(model2, "foo").Wait());
+}