[Chromecast] Correct libcast_governor behavior.

chromecast/media/cma/backend/alsa/post_processors/governor_unittest.cc

Index: chromecast/media/cma/backend/alsa/post_processors/governor_unittest.cc
diff --git a/chromecast/media/cma/backend/alsa/post_processors/governor_unittest.cc b/chromecast/media/cma/backend/alsa/post_processors/governor_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..30598cc658ddc6fe83e7e6e819060749907cec0a
--- /dev/null
+++ b/chromecast/media/cma/backend/alsa/post_processors/governor_unittest.cc
@@ -0,0 +1,151 @@
+// Copyright 2017 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 <cmath>
+#include <cstdint>
+#include <limits>
+#include <string>
+#include <vector>
+
+#include "base/macros.h"
+#include "base/memory/ptr_util.h"
+#include "base/strings/stringprintf.h"
+#include "chromecast/media/cma/backend/alsa/post_processors/governor.h"
+#include "media/base/audio_bus.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace chromecast {
+namespace media {
+
+namespace {
+
+const char* kConfigTemplate =
+    R"config({"onset_volume": %f, "clamp_multiplier": %f})config";
+
+const int kNumChannels = 2;
+const float kDefaultClamp = 0.6f;
+const int kNumFrames = 100;
+const float kFrequency = 1.0f / kNumFrames;
+const int kBytesPerSample = sizeof(int32_t);
+const int kSampleRate = 44100;
+
+std::string MakeConfigString(float onset_volume, float clamp_multiplier) {
+  return base::StringPrintf(kConfigTemplate, onset_volume, clamp_multiplier);
+}
+
+// Frequency is in frames (frequency = frequency_in_hz / sample rate)
+std::unique_ptr<::media::AudioBus> GetSineData(size_t frames, float frequency) {
+  auto data = ::media::AudioBus::Create(kNumChannels, frames);
+  std::vector<int32_t> sine(frames * 2);
+  for (size_t i = 0; i < frames; ++i) {
+    sine[i * 2] = sin(static_cast<float>(i) * frequency * 2 * M_PI) *
+                  std::numeric_limits<int32_t>::max();
+    sine[i * 2 + 1] = cos(static_cast<float>(i) * frequency * 2 * M_PI) *
+                      std::numeric_limits<int32_t>::max();
+  }
+  data->FromInterleaved(sine.data(), frames, kBytesPerSample);
+  return data;
+}
+
+std::vector<float*> GetDataChannels(::media::AudioBus* audio) {
+  std::vector<float*> data(kNumChannels);
+  for (int i = 0; i < kNumChannels; ++i) {
+    data[i] = audio->channel(i);
+  }
+  return data;
+}
+
+void ScaleData(const std::vector<float*>& data, int frames, float scale) {
+  for (size_t ch = 0; ch < data.size(); ++ch) {
+    for (int f = 0; f < frames; ++f) {
+      data[ch][f] *= scale;
+    }
+  }
+}
+
+void CompareData(const std::vector<float*>& expected,
+                 const std::vector<float*>& actual,
+                 int frames) {
+  ASSERT_EQ(expected.size(), actual.size());
+  for (size_t ch = 0; ch < expected.size(); ++ch) {
+    for (int f = 0; f < frames; ++f) {
+      EXPECT_FLOAT_EQ(expected[ch][f], actual[ch][f])
+          << "ch: " << ch << " f: " << f;
+    }
+  }
+}
+
+}  // namespace
+
+class GovernorTest : public ::testing::TestWithParam<float> {
+ protected:
+  GovernorTest() = default;
+  ~GovernorTest() = default;
+  void SetUp() override {
+    clamp_ = kDefaultClamp;
+    onset_volume_ = GetParam();
+    std::string config = MakeConfigString(onset_volume_, clamp_);
+    governor_ = base::MakeUnique<Governor>(config, kNumChannels);
+    governor_->SetSlewTimeMsForTest(0);
+    governor_->SetSampleRate(kSampleRate);
+
+    data_bus_ = GetSineData(kNumFrames, kFrequency);
+    expected_bus_ = GetSineData(kNumFrames, kFrequency);
+    data_ = GetDataChannels(data_bus_.get());
+    expected_ = GetDataChannels(expected_bus_.get());
+  }
+
+  void CompareBuffers() { CompareData(expected_, data_, kNumFrames); }
+
+  void ProcessFrames(float volume) {
+    EXPECT_EQ(governor_->ProcessFrames(data_, kNumFrames, volume), 0);
+  }
+
+  float clamp_;
+  float onset_volume_;
+  std::unique_ptr<Governor> governor_;
+  std::unique_ptr<::media::AudioBus> data_bus_;
+  std::unique_ptr<::media::AudioBus> expected_bus_;
+  std::vector<float*> data_;
+  std::vector<float*> expected_;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(GovernorTest);
+};
+
+TEST_P(GovernorTest, ZeroVolume) {
+  ProcessFrames(0.0f);
+  if (onset_volume_ <= 0.0f) {
+    ScaleData(expected_, kNumFrames, clamp_);
+  }
+  CompareBuffers();
+}
+
+TEST_P(GovernorTest, EpsilonBelowOnset) {
+  float volume = onset_volume_ - std::numeric_limits<float>::epsilon();
+  ProcessFrames(volume);
+  CompareBuffers();
+}
+
+TEST_P(GovernorTest, EpsilonAboveOnset) {
+  float volume = onset_volume_ + std::numeric_limits<float>::epsilon();
+  ProcessFrames(volume);
+  ScaleData(expected_, kNumFrames, clamp_);
+  CompareBuffers();
+}
+
+TEST_P(GovernorTest, MaxVolume) {
+  ProcessFrames(1.0);
+  if (onset_volume_ <= 1.0) {
+    ScaleData(expected_, kNumFrames, clamp_);
+  }
+  CompareBuffers();
+}
+
+INSTANTIATE_TEST_CASE_P(GovernorClampVolumeTest,
+                        GovernorTest,
+                        ::testing::Values(0.0f, 0.1f, 0.5f, 0.9f, 1.0f, 1.1f));
+
+}  // namespace media
+}  // namespace chromecast