[TTS] Add aggregation of CTR metrics to the CS component.

components/contextual_search/browser/ctr_aggregator_unittest.cc

+// 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 "components/contextual_search/browser/ctr_aggregator.h"
+
+#include <unordered_map>
+
+#include "base/gtest_prod_util.h"
+#include "base/logging.h"
+#include "base/values.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using base::Value;
+
+namespace {
+const int kTestWeek = 2500;
+}
+
+namespace contextual_search {
+
+class CTRAggregatorTest : public testing::Test {
+ public:
+  CTRAggregatorTest() {}
+  ~CTRAggregatorTest() override {}
+
+  class WeeklyActivityStorageStub : public WeeklyActivityStorage {
+   public:
+    WeeklyActivityStorageStub();
+
+   private:
+    int ReadStorage(std::string storage_bucket) override;
+    void WriteStorage(std::string storage_key, int value) override;
+
+    typedef std::unordered_map<std::string, int> hashmap;
+    hashmap weeks_;
+  };
+
+  // Test helpers
+  void Fill4Weeks();  // Fill 4 weeks with 2 impressions, 1 click.
+
+  // The class under test.
+  std::unique_ptr<CTRAggregator> aggregator_;
+
+ protected:
+  // The storage stub.
+  std::unique_ptr<WeeklyActivityStorage> storage_;
+
+  void SetUp() override {
+    storage_.reset(new WeeklyActivityStorageStub());
+    aggregator_.reset(new CTRAggregator(*storage_.get(), kTestWeek));
+  }
+
+  void TearDown() override {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(CTRAggregatorTest);
+};
+
+CTRAggregatorTest::WeeklyActivityStorageStub::WeeklyActivityStorageStub()
+    : WeeklyActivityStorage(4) {}
+
+int CTRAggregatorTest::WeeklyActivityStorageStub::ReadStorage(
+    std::string storage_bucket) {
+  return weeks_[storage_bucket];
+}
+
+void CTRAggregatorTest::WeeklyActivityStorageStub::WriteStorage(
+    std::string storage_bucket,
+    int value) {
+  weeks_[storage_bucket] = value;
+}
+
+void CTRAggregatorTest::Fill4Weeks() {
+  int weeks_to_record = 4;
+  for (int i = 0; i < weeks_to_record; i++) {
+    aggregator_->RecordImpression(true);
+    aggregator_->RecordImpression(false);
+    EXPECT_FALSE(aggregator_->HasPrevious28DayData());
+    aggregator_->IncrementWeek(1);
+  }
+  EXPECT_TRUE(aggregator_->HasPrevious28DayData());
+}
+
+// NaN has the property that it is not equal to itself.
+#define EXPECT_NAN(x) EXPECT_NE(x, x)
+
+TEST_F(CTRAggregatorTest, SimpleOperationTest) {
+  aggregator_->RecordImpression(true);
+  aggregator_->RecordImpression(false);
+  EXPECT_FALSE(aggregator_->HasPreviousWeekData());
+  EXPECT_EQ(0, aggregator_->GetPreviousWeekImpressions());
+  EXPECT_NAN(aggregator_->GetPreviousWeekCTR());
+
+  aggregator_->IncrementWeek(1);
+  EXPECT_TRUE(aggregator_->HasPreviousWeekData());
+  EXPECT_EQ(2, aggregator_->GetPreviousWeekImpressions());
+  EXPECT_FLOAT_EQ(0.5f, aggregator_->GetPreviousWeekCTR());
+}
+
+TEST_F(CTRAggregatorTest, MultiWeekTest) {
+  Fill4Weeks();
+  aggregator_->RecordImpression(false);
+  aggregator_->IncrementWeek(1);
+  EXPECT_TRUE(aggregator_->HasPrevious28DayData());
+  EXPECT_FLOAT_EQ(static_cast<float>(3.0 / 7),
+                  aggregator_->GetPrevious28DayCTR());
+  aggregator_->RecordImpression(false);
+  aggregator_->IncrementWeek(1);
+  EXPECT_TRUE(aggregator_->HasPrevious28DayData());
+  EXPECT_FLOAT_EQ(static_cast<float>(2.0 / 6),
+                  aggregator_->GetPrevious28DayCTR());
+}
+
+TEST_F(CTRAggregatorTest, SkipOneWeekTest) {
+  Fill4Weeks();
+  aggregator_->IncrementWeek(1);
+  EXPECT_EQ(0, aggregator_->GetPreviousWeekCTR());
+  EXPECT_FLOAT_EQ(static_cast<float>(3.0 / 6),
+                  aggregator_->GetPrevious28DayCTR());
+}
+
+TEST_F(CTRAggregatorTest, SkipThreeWeeksTest) {
+  Fill4Weeks();
+  aggregator_->IncrementWeek(3);
+  EXPECT_EQ(0, aggregator_->GetPreviousWeekCTR());
+  EXPECT_FLOAT_EQ(static_cast<float>(1.0 / 2),
+                  aggregator_->GetPrevious28DayCTR());
+}
+
+TEST_F(CTRAggregatorTest, SkipFourWeeksTest) {
+  Fill4Weeks();
+  aggregator_->IncrementWeek(4);
+  EXPECT_EQ(0, aggregator_->GetPreviousWeekCTR());
+  EXPECT_EQ(0, aggregator_->GetPrevious28DayCTR());
+}
+
+}  // namespace contextual_search