Adding second layer of the echo canceller 3 functionality.

webrtc/modules/audio_processing/test/echo_canceller_test_tools_unittest.cc

+/*
+ *  Copyright (c) 2017 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/test/echo_canceller_test_tools.h"
+
+#include <vector>
+
+#include "webrtc/base/array_view.h"
+#include "webrtc/base/checks.h"
+#include "webrtc/base/random.h"
+#include "webrtc/test/gtest.h"
+
+namespace webrtc {
+
+TEST(EchoCancellerTestTools, FloatDelayBuffer) {
+  constexpr size_t kDelay = 10;
+  DelayBuffer<float> delay_buffer(kDelay);
+  std::vector<float> v(1000, 0.f);
+  for (size_t k = 0; k < v.size(); ++k) {
+    v[k] = k;
+  }
+  std::vector<float> v_delayed = v;
+  constexpr size_t kBlockSize = 50;
+  for (size_t k = 0; k < rtc::CheckedDivExact(v.size(), kBlockSize); ++k) {
+    delay_buffer.Delay(
+        rtc::ArrayView<const float>(&v[k * kBlockSize], kBlockSize),
+        rtc::ArrayView<float>(&v_delayed[k * kBlockSize], kBlockSize));
+  }
+  for (size_t k = kDelay; k < v.size(); ++k) {
+    EXPECT_EQ(v[k - kDelay], v_delayed[k]);
+  }
+}
+
+TEST(EchoCancellerTestTools, IntDelayBuffer) {
+  constexpr size_t kDelay = 10;
+  DelayBuffer<int> delay_buffer(kDelay);
+  std::vector<int> v(1000, 0);
+  for (size_t k = 0; k < v.size(); ++k) {
+    v[k] = k;
+  }
+  std::vector<int> v_delayed = v;
+  const size_t kBlockSize = 50;
+  for (size_t k = 0; k < rtc::CheckedDivExact(v.size(), kBlockSize); ++k) {
+    delay_buffer.Delay(
+        rtc::ArrayView<const int>(&v[k * kBlockSize], kBlockSize),
+        rtc::ArrayView<int>(&v_delayed[k * kBlockSize], kBlockSize));
+  }
+  for (size_t k = kDelay; k < v.size(); ++k) {
+    EXPECT_EQ(v[k - kDelay], v_delayed[k]);
+  }
+}
+
+TEST(EchoCancellerTestTools, RandomizeSampleVector) {
+  Random random_generator(42U);
+  std::vector<float> v(50, 0.f);
+  std::vector<float> v_ref = v;
+  RandomizeSampleVector(&random_generator, v);
+  EXPECT_NE(v, v_ref);
+  v_ref = v;
+  RandomizeSampleVector(&random_generator, v);
+  EXPECT_NE(v, v_ref);
+}
+
+}  // namespace webrtc