Changed ramping functionality of the AudioMixer.

webrtc/modules/audio_mixer/audio_frame_manipulator_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 <algorithm>
+
+#include "webrtc/modules/audio_mixer/audio_frame_manipulator.h"
+#include "webrtc/modules/include/module_common_types.h"
+#include "webrtc/test/gtest.h"
+
+namespace webrtc {
+namespace {
+
+void FillFrameWithConstants(size_t samples_per_channel,
+                            size_t number_of_channels,
+                            int16_t value,
+                            AudioFrame* frame) {
+  frame->num_channels_ = number_of_channels;
+  frame->samples_per_channel_ = samples_per_channel;
+  std::fill(frame->data_,
+            frame->data_ + samples_per_channel * number_of_channels, value);
+}
+}  // namespace
+
+TEST(AudioFrameManipulator, CompareForwardRampWithExpectedResultStereo) {
+  constexpr int kSamplesPerChannel = 5;
+  constexpr int kNumberOfChannels = 2;
+
+  // Create a frame with values 5, 5, 5, ... and channels & samples as above.
+  AudioFrame frame;
+  FillFrameWithConstants(kSamplesPerChannel, kNumberOfChannels, 5, &frame);
+
+  Ramp(0.0f, 1.0f, &frame);
+
+  const int total_samples = kSamplesPerChannel * kNumberOfChannels;
+  const int16_t expected_result[total_samples] = {0, 0, 1, 1, 2, 2, 3, 3, 4, 4};
+  EXPECT_TRUE(
+      std::equal(frame.data_, frame.data_ + total_samples, expected_result));
+}
+
+TEST(AudioFrameManipulator, CompareBackwardRampWithExpectedResultMono) {
+  constexpr int kSamplesPerChannel = 5;
+  constexpr int kNumberOfChannels = 1;
+
+  // Create a frame with values 5, 5, 5, ... and channels & samples as above.
+  AudioFrame frame;
+  FillFrameWithConstants(kSamplesPerChannel, kNumberOfChannels, 5, &frame);
+
+  Ramp(1.0f, 0.0f, &frame);
+
+  const int total_samples = kSamplesPerChannel * kNumberOfChannels;
+  const int16_t expected_result[total_samples] = {5, 4, 3, 2, 1};
+  EXPECT_TRUE(
+      std::equal(frame.data_, frame.data_ + total_samples, expected_result));
+}
+
+}  // namespace webrtc