Create a PrefStore in support of Blimp metrics collection.

blimp/engine/common/blimp_pref_store_unittest.cc

Index: blimp/engine/common/blimp_pref_store_unittest.cc
diff --git a/blimp/engine/common/blimp_pref_store_unittest.cc b/blimp/engine/common/blimp_pref_store_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..f31b5b208df2d595ba0f980a589c0803ced2388f
--- /dev/null
+++ b/blimp/engine/common/blimp_pref_store_unittest.cc
@@ -0,0 +1,87 @@
+// 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/engine/common/blimp_pref_store.h"
+
+#include "base/values.h"
+#include "components/prefs/pref_store_observer_mock.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace blimp {
+namespace engine {
+namespace {
+const char kTestPref[] = "test.pref";
+
+class BlimpPrefStoreTest : public testing::Test {
+ public:
+  BlimpPrefStoreTest() { }
+
+  void SetUp() override { store_ = new BlimpPrefStore(); }
+ protected:
+  scoped_refptr<BlimpPrefStore> store_;
+  PrefStoreObserverMock observer_;
+};
+
+TEST_F(BlimpPrefStoreTest, SetGetValue) {
+  const base::Value* value = NULL;
+  base::Value* mutable_value = NULL;
+  EXPECT_FALSE(store_->GetValue(kTestPref, &value));
+  EXPECT_FALSE(store_->GetMutableValue(kTestPref, &mutable_value));
+
+  store_->SetValue(kTestPref, make_scoped_ptr(new base::FundamentalValue(42)),
+                   WriteablePrefStore::DEFAULT_PREF_WRITE_FLAGS);
+  EXPECT_TRUE(store_->GetValue(kTestPref, &value));
+  EXPECT_TRUE(base::FundamentalValue(42).Equals(value));
+  EXPECT_TRUE(store_->GetMutableValue(kTestPref, &mutable_value));
+  EXPECT_TRUE(base::FundamentalValue(42).Equals(mutable_value));
+
+  store_->RemoveValue(kTestPref, WriteablePrefStore::DEFAULT_PREF_WRITE_FLAGS);
+  EXPECT_FALSE(store_->GetValue(kTestPref, &value));
+  EXPECT_FALSE(store_->GetMutableValue(kTestPref, &mutable_value));
+}
+
+TEST_F(BlimpPrefStoreTest, GetSetObserver) {
+  // Starts with no observers.
+  EXPECT_FALSE(store_->HasObservers());
+  // Add one.

[Kevin M, 2016/04/20 23:03:35]

Add newlines before commented blocks, so...

EXPECT_FALSE(...)

// Add one
store_->AddObserver(...)
EXPECT_TRUE(...)

// Remove only observer.


Ditto for other comments in this file.

[Jess, 2016/04/20 23:32:06]

Done.

+  store_->AddObserver(&observer_);
+  EXPECT_TRUE(store_->HasObservers());
+  // Remove only observer.
+  store_->RemoveObserver(&observer_);
+  EXPECT_FALSE(store_->HasObservers());
+}
+
+TEST_F(BlimpPrefStoreTest, CallObserver) {
+  // With observer included.
+  store_->AddObserver(&observer_);
+  // Triggers on SetValue.
+  store_->SetValue(kTestPref, make_scoped_ptr(new base::FundamentalValue(42)),
+                   WriteablePrefStore::DEFAULT_PREF_WRITE_FLAGS);
+  observer_.VerifyAndResetChangedKey(kTestPref);
+  // And RemoveValue.
+  store_->RemoveValue(kTestPref, WriteablePrefStore::DEFAULT_PREF_WRITE_FLAGS);
+  observer_.VerifyAndResetChangedKey(kTestPref);
+  // But not SetValueSilently.
+  store_->SetValueSilently(kTestPref,
+                           make_scoped_ptr(new base::FundamentalValue(42)),
+                           WriteablePrefStore::DEFAULT_PREF_WRITE_FLAGS);
+  EXPECT_EQ(0u, observer_.changed_keys.size());
+  // On multiple RemoveValues only the first one triggers observer.
+  store_->RemoveValue(kTestPref, WriteablePrefStore::DEFAULT_PREF_WRITE_FLAGS);
+  observer_.VerifyAndResetChangedKey(kTestPref);
+  store_->RemoveValue(kTestPref, WriteablePrefStore::DEFAULT_PREF_WRITE_FLAGS);
+  EXPECT_EQ(0u, observer_.changed_keys.size());
+
+  // Doesn't make call on removed observers.
+  store_->RemoveObserver(&observer_);
+  store_->SetValue(kTestPref, make_scoped_ptr(new base::FundamentalValue(42)),
+                   WriteablePrefStore::DEFAULT_PREF_WRITE_FLAGS);
+  store_->RemoveValue(kTestPref, WriteablePrefStore::DEFAULT_PREF_WRITE_FLAGS);
+  EXPECT_EQ(0u, observer_.changed_keys.size());
+}
+
+}  // namespace
+}  // namespace engine
+}  // namespace blimp