Add algorithm for Residual Echo Detector.

webrtc/modules/audio_processing/echo_detector/circular_buffer_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/audio_processing/echo_detector/circular_buffer.h"
+#include "webrtc/test/gtest.h"
+
+namespace webrtc {
+
+TEST(CircularBufferTests, LessThanMaxTest) {
+  CircularBuffer test_buffer(3);
+  test_buffer.Push(1.f);
+  test_buffer.Push(2.f);
+  EXPECT_EQ(rtc::Optional<float>(1.f), test_buffer.Pop());
+  EXPECT_EQ(rtc::Optional<float>(2.f), test_buffer.Pop());
+}
+
+TEST(CircularBufferTests, FillTest) {
+  CircularBuffer test_buffer(3);
+  test_buffer.Push(1.f);
+  test_buffer.Push(2.f);
+  test_buffer.Push(3.f);
+  EXPECT_EQ(rtc::Optional<float>(1.f), test_buffer.Pop());
+  EXPECT_EQ(rtc::Optional<float>(2.f), test_buffer.Pop());
+  EXPECT_EQ(rtc::Optional<float>(3.f), test_buffer.Pop());
+}
+
+TEST(CircularBufferTests, OverflowTest) {
+  CircularBuffer test_buffer(3);
+  test_buffer.Push(1.f);
+  test_buffer.Push(2.f);
+  test_buffer.Push(3.f);
+  test_buffer.Push(4.f);
+  // Because the circular buffer has a size of 3, the first insert should have
+  // been forgotten.
+  EXPECT_EQ(rtc::Optional<float>(2.f), test_buffer.Pop());
+  EXPECT_EQ(rtc::Optional<float>(3.f), test_buffer.Pop());
+  EXPECT_EQ(rtc::Optional<float>(4.f), test_buffer.Pop());
+}
+
+TEST(CircularBufferTests, ReadFromEmpty) {
+  CircularBuffer test_buffer(3);
+  EXPECT_EQ(rtc::Optional<float>(), test_buffer.Pop());
+}
+
+}  // namespace webrtc