Added first layer of the echo canceller 3 functionality

webrtc/modules/audio_processing/aec3/cascaded_biquad_filter_unittest.cc

Index: webrtc/modules/audio_processing/aec3/cascaded_biquad_filter_unittest.cc
diff --git a/webrtc/modules/audio_processing/aec3/cascaded_biquad_filter_unittest.cc b/webrtc/modules/audio_processing/aec3/cascaded_biquad_filter_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..7628a8814e5dfbea6a917c9301a1f480f8a53fe3
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+++ b/webrtc/modules/audio_processing/aec3/cascaded_biquad_filter_unittest.cc
@@ -0,0 +1,98 @@
+/*
+ *  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/aec3/cascaded_biquad_filter.h"
+
+#include <vector>
+
+#include "webrtc/test/gtest.h"
+
+namespace webrtc {
+
+namespace {
+
+// Coefficients for a second order Butterworth high-pass filter with cutoff
+// frequency 100 Hz.
+const CascadedBiQuadFilter::BiQuadCoefficients kHighPassFilterCoefficients = {
+    {0.97261f, -1.94523f, 0.97261f},
+    {-1.94448f, 0.94598f}};
+
+const CascadedBiQuadFilter::BiQuadCoefficients kTransparentCoefficients = {
+    {1.f, 0.f, 0.f},
+    {0.f, 0.f}};
+
+const CascadedBiQuadFilter::BiQuadCoefficients kBlockingCoefficients = {
+    {0.f, 0.f, 0.f},
+    {0.f, 0.f}};
+
+std::vector<float> CreateInputWithIncreasingValues(size_t vector_length) {
+  std::vector<float> v(vector_length);
+  for (size_t k = 0; k < v.size(); ++k) {
+    v[k] = k;
+  }
+  return v;
+}
+
+}  // namespace
+
+// Verifies that the filter applies an effect which removes the input signal.
+// The test also verifies that the in-place Process API call works as intended.
+TEST(CascadedBiquadFilter, BlockingConfiguration) {
+  std::vector<float> values = CreateInputWithIncreasingValues(1000);
+
+  CascadedBiQuadFilter filter(kBlockingCoefficients, 1);
+  filter.Process(values);
+
+  EXPECT_EQ(std::vector<float>(1000, 0.f), values);
+}
+
+// Verifies that the filter is able to form a zero-mean output from a
+// non-zeromean input signal when coefficients for a high-pass filter are
+// applied. The test also verifies that the filter works with multiple biquads.
+TEST(CascadedBiquadFilter, HighPassConfiguration) {
+  std::vector<float> values(1000);
+  for (size_t k = 0; k < values.size(); ++k) {
+    values[k] = 1.f;
+  }
+
+  CascadedBiQuadFilter filter(kHighPassFilterCoefficients, 2);
+  filter.Process(values);
+
+  for (size_t k = values.size() / 2; k < values.size(); ++k) {
+    EXPECT_NEAR(0.f, values[k], 1e-4);
+  }
+}
+
+// Verifies that the filter is able to produce a transparent effect with no
+// impact on the data when the proper coefficients are applied. The test also
+// verifies that the non-in-place Process API call works as intended.
+TEST(CascadedBiquadFilter, TransparentConfiguration) {
+  const std::vector<float> input = CreateInputWithIncreasingValues(1000);
+  std::vector<float> output(input.size());
+
+  CascadedBiQuadFilter filter(kTransparentCoefficients, 1);
+  filter.Process(input, output);
+
+  EXPECT_EQ(input, output);
+}
+
+#if RTC_DCHECK_IS_ON && GTEST_HAS_DEATH_TEST && !defined(WEBRTC_ANDROID)
+// Verifies that the check of the lengths for the input and output works for the
+// non-in-place call.
+TEST(CascadedBiquadFilter, InputSizeCheckVerification) {
+  const std::vector<float> input = CreateInputWithIncreasingValues(10);
+  std::vector<float> output(input.size() - 1);
+
+  CascadedBiQuadFilter filter(kTransparentCoefficients, 1);
+  EXPECT_DEATH(filter.Process(input, output), "");
+}
+#endif
+
+}  // namespace webrtc