Refactor QualityScaler and MovingAverage

webrtc/modules/video_coding/utility/moving_average_unittest.cc

+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/video_coding/utility/moving_average.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+TEST(MovingAverageTest, GetAverage) {
+  webrtc::MovingAverage moving_average;
+  moving_average.AddSample(1);
+  moving_average.AddSample(1);
+  moving_average.AddSample(3);
+  moving_average.AddSample(3);
+  EXPECT_EQ(moving_average.GetAverage(4), 2);
+  EXPECT_EQ(moving_average.GetAverage(2), 3);
+}
+
+TEST(MovingAverageTest, Reset) {
+  webrtc::MovingAverage moving_average;
+  moving_average.AddSample(1);
+  EXPECT_EQ(1, moving_average.GetAverage(1));
+  moving_average.Reset();
+  EXPECT_EQ(0, moving_average.GetAverage(1));
+}
+
+TEST(MovingAverageTest, ManySamples) {
+  webrtc::MovingAverage moving_average(10);
+  for (int i = 1; i < 11; i++) {
+    moving_average.AddSample(i);
+  }
+  EXPECT_EQ(moving_average.GetAverage(), 5);
+  moving_average.Reset();
+  for (int i = 1; i < 2001; i++) {
+    moving_average.AddSample(i);
+  }
+  EXPECT_EQ(moving_average.GetAverage(), 1995);
+}