Adding a previews object, PreviewsDataSavings

components/previews/previews_data_savings_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/previews/previews_data_savings.h"
+
+#include <stdint.h>
+
+#include <memory>
+#include <string>
+
+#include "components/data_reduction_proxy/core/common/data_savings_recorder.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace previews {
+
+namespace {
+
+class TestDataSavingsRecorder
+    : public data_reduction_proxy::DataSavingsRecorder {
+ public:
+  TestDataSavingsRecorder()
+      : data_saver_enabled_(false), data_used_(0), original_size_(0) {}
+  ~TestDataSavingsRecorder() {}
+
+  // data_reduction_proxy::DataSavingsRecorder implementation:
+  bool UpdateDataSavings(const std::string& host,
+                         int64_t data_used,
+                         int64_t original_size) override {
+    if (!data_saver_enabled_) {
+      return false;
+    }
+    last_host_ = host;
+    data_used_ += data_used;
+    original_size_ += original_size;
+    return true;
+  }
+
+  void set_data_saver_enabled(bool data_saver_enabled) {
+    data_saver_enabled_ = data_saver_enabled;
+  }
+
+  std::string last_host() const { return last_host_; }
+
+  int64_t data_used() const { return data_used_; }
+
+  int64_t original_size() const { return original_size_; }
+
+ private:
+  bool data_saver_enabled_;
+  std::string last_host_;
+  int64_t data_used_;
+  int64_t original_size_;
+};
+
+}  // namespace
+
+class PreviewsDataSavingsTest : public testing::Test {
+ public:
+  PreviewsDataSavingsTest()
+      : test_data_savings_recorder_(new TestDataSavingsRecorder()),
+        data_savings_(
+            new PreviewsDataSavings(test_data_savings_recorder_.get())) {}
+  ~PreviewsDataSavingsTest() override {}
+
+  PreviewsDataSavings* data_savings() const { return data_savings_.get(); }
+
+  TestDataSavingsRecorder* test_data_savings_recorder() const {
+    return test_data_savings_recorder_.get();
+  }
+
+ private:
+  std::unique_ptr<TestDataSavingsRecorder> test_data_savings_recorder_;
+  std::unique_ptr<PreviewsDataSavings> data_savings_;
+};
+
+TEST_F(PreviewsDataSavingsTest, RecordDataSavings) {
+  int64_t original_size = 200;
+  int64_t data_used = 100;
+  std::string host = "host";
+
+  EXPECT_EQ(0, test_data_savings_recorder()->data_used());
+  EXPECT_EQ(0, test_data_savings_recorder()->original_size());
+  test_data_savings_recorder()->set_data_saver_enabled(false);
+
+  data_savings()->RecordDataSavings(host, data_used, original_size);
+
+  EXPECT_EQ(0, test_data_savings_recorder()->data_used());
+  EXPECT_EQ(0, test_data_savings_recorder()->original_size());
+  EXPECT_EQ(std::string(), test_data_savings_recorder()->last_host());
+  test_data_savings_recorder()->set_data_saver_enabled(true);
+
+  data_savings()->RecordDataSavings(host, data_used, original_size);
+
+  EXPECT_EQ(data_used, test_data_savings_recorder()->data_used());
+  EXPECT_EQ(original_size, test_data_savings_recorder()->original_size());
+  EXPECT_EQ(host, test_data_savings_recorder()->last_host());
+}
+
+}  // namespace previews