Add a PersistentStore to FeatureEngagementTracker

components/feature_engagement_tracker/internal/persistent_store_unittest.cc

+// Copyright 2017 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/feature_engagement_tracker/internal/persistent_store.h"
+
+#include <map>
+
+#include "base/files/file_path.h"
+#include "base/memory/ptr_util.h"
+#include "base/optional.h"
+#include "components/feature_engagement_tracker/internal/proto/event.pb.h"
+#include "components/feature_engagement_tracker/internal/test/event_util.h"
+#include "components/leveldb_proto/proto_database.h"
+#include "components/leveldb_proto/testing/fake_db.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace feature_engagement_tracker {
+
+namespace {
+
+void VerifyEventsInListAndMap(const std::map<std::string, Event>& map,
+                              const std::vector<Event>& list) {
+  ASSERT_EQ(map.size(), list.size());
+
+  for (const auto& event : list) {
+    const auto& it = map.find(event.name());
+    ASSERT_NE(map.end(), it);
+    test::VerifyEventsEqual(&event, &it->second);
+  }
+}
+
+class PersistentStoreTest : public ::testing::Test {
+ public:
+  PersistentStoreTest()
+      : db_(nullptr),
+        storage_dir_(FILE_PATH_LITERAL("/persistent/store/lalala")) {
+    load_callback_ =
+        base::Bind(&PersistentStoreTest::LoadCallback, base::Unretained(this));
+  }
+
+  void TearDown() override {
+    db_events_.clear();
+    db_ = nullptr;
+    store_.reset();
+  }
+
+ protected:
+  void SetUpDb() {

[nyquist, 2017/05/11 17:08:03]

Nit: I think we're allowed to use all-caps for things like URL etc., in C++? Do
we want that for DB, like in the FakeDB class name? Don't feel strongly.
Technically it's database and not DataBase anyway, so :-p

[David Trainor- moved to gerrit, 2017/05/11 19:30:28]

Done.

+    DCHECK(!db_);
+    DCHECK(!store_);
+
+    db_ = new leveldb_proto::test::FakeDB<Event>(&db_events_);

[nyquist, 2017/05/11 17:08:03]

Nit: I know we discussed offline... Could you see once more if it's possible to
not new up a raw thing?
If you do that and it still looks messed up, then just leave as is.

[David Trainor- moved to gerrit, 2017/05/11 19:30:28]

Done.

+    store_.reset(new PersistentStore(
+        storage_dir_,
+        base::WrapUnique<leveldb_proto::ProtoDatabase<Event>>(db_)));
+  }
+
+  void LoadCallback(bool success, std::unique_ptr<std::vector<Event>> events) {
+    load_successful_ = success;
+    load_results_ = std::move(events);
+  }
+
+  // Callback results.
+  base::Optional<bool> load_successful_;

[nyquist, 2017/05/11 17:08:03]

Ooooh... I like so much!

[David Trainor- moved to gerrit, 2017/05/11 19:30:28]

Acknowledged.

+  std::unique_ptr<std::vector<Event>> load_results_;
+
+  Store::OnLoadedCallback load_callback_;
+  std::map<std::string, Event> db_events_;
+  leveldb_proto::test::FakeDB<Event>* db_;
+  std::unique_ptr<Store> store_;
+
+  // Constant test data.
+  base::FilePath storage_dir_;
+};
+
+}  // namespace
+
+TEST_F(PersistentStoreTest, StorageDirectory) {
+  SetUpDb();
+  store_->Load(load_callback_);
+  EXPECT_EQ(storage_dir_, db_->GetDirectory());
+}
+
+TEST_F(PersistentStoreTest, SuccessfulInitAndLoadEmptyStore) {
+  SetUpDb();
+
+  store_->Load(load_callback_);
+
+  // The initialize should not trigger a response to the callback.
+  db_->InitCallback(true);
+  EXPECT_FALSE(load_successful_.has_value());
+
+  // The load should trigger a response to the callback.
+  db_->LoadCallback(true);
+  EXPECT_TRUE(load_successful_.value());
+
+  // Validate that we have no entries.
+  EXPECT_NE(nullptr, load_results_);
+  EXPECT_TRUE(load_results_->empty());
+}
+
+TEST_F(PersistentStoreTest, SuccessfulInitAndLoadWithEvents) {
+  // Populate fake Event entries.
+  Event event1;
+  event1.set_name("event1");
+  test::SetEventCountForDay(&event1, 1, 1);
+
+  Event event2;
+  event2.set_name("event2");
+  test::SetEventCountForDay(&event2, 1, 3);
+  test::SetEventCountForDay(&event2, 2, 5);
+
+  db_events_.insert(std::pair<std::string, Event>(event1.name(), event1));
+  db_events_.insert(std::pair<std::string, Event>(event2.name(), event2));
+
+  SetUpDb();
+
+  // The initialize should not trigger a response to the callback.
+  store_->Load(load_callback_);
+  db_->InitCallback(true);
+  EXPECT_FALSE(load_successful_.has_value());
+
+  // The load should trigger a response to the callback.
+  db_->LoadCallback(true);
+  EXPECT_TRUE(load_successful_.value());
+  EXPECT_NE(nullptr, load_results_);
+
+  // Validate that we have the two events that we expect.
+  VerifyEventsInListAndMap(db_events_, *load_results_);
+}
+
+TEST_F(PersistentStoreTest, SuccessfulInitBadLoad) {
+  SetUpDb();
+
+  store_->Load(load_callback_);
+
+  // The initialize should not trigger a response to the callback.
+  db_->InitCallback(true);
+  EXPECT_FALSE(load_successful_.has_value());
+
+  // The load will fail and should trigger the callback.
+  db_->LoadCallback(false);
+  EXPECT_FALSE(load_successful_.value());
+  EXPECT_FALSE(store_->IsReady());
+}
+
+TEST_F(PersistentStoreTest, BadInit) {
+  SetUpDb();
+
+  store_->Load(load_callback_);
+
+  // The initialize will fail and should trigger the callback.
+  db_->InitCallback(false);
+  EXPECT_FALSE(load_successful_.value());
+  EXPECT_FALSE(store_->IsReady());
+}
+
+TEST_F(PersistentStoreTest, IsReady) {
+  SetUpDb();
+  EXPECT_FALSE(store_->IsReady());
+
+  store_->Load(load_callback_);
+  EXPECT_FALSE(store_->IsReady());
+
+  db_->InitCallback(true);
+  EXPECT_FALSE(store_->IsReady());
+
+  db_->LoadCallback(true);
+  EXPECT_TRUE(store_->IsReady());
+}
+
+TEST_F(PersistentStoreTest, WriteEvent) {
+  SetUpDb();
+
+  store_->Load(load_callback_);
+  db_->InitCallback(true);
+  db_->LoadCallback(true);
+
+  Event event;
+  event.set_name("event");
+  test::SetEventCountForDay(&event, 1, 2);
+
+  store_->WriteEvent(event);
+  db_->UpdateCallback(true);
+
+  EXPECT_EQ(1U, db_events_.size());
+
+  const auto& it = db_events_.find("event");
+  EXPECT_NE(db_events_.end(), it);
+  test::VerifyEventsEqual(&event, &it->second);
+}
+
+}  // namespace feature_engagement_tracker