Add a general PostProcessorUnittest.

chromecast/media/cma/backend/alsa/post_processors/post_processor_unittest.h

Index: chromecast/media/cma/backend/alsa/post_processors/post_processor_unittest.h
diff --git a/chromecast/media/cma/backend/alsa/post_processors/post_processor_unittest.h b/chromecast/media/cma/backend/alsa/post_processors/post_processor_unittest.h
new file mode 100644
index 0000000000000000000000000000000000000000..38149c64a88b53ae649ae88ec9018a48837ff4c6
--- /dev/null
+++ b/chromecast/media/cma/backend/alsa/post_processors/post_processor_unittest.h
@@ -0,0 +1,80 @@
+// 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.
+
+#ifndef CHROMECAST_MEDIA_CMA_BACKEND_ALSA_POST_PROCESSORS_POST_PROCESSOR_UNITTEST_H_
+#define CHROMECAST_MEDIA_CMA_BACKEND_ALSA_POST_PROCESSORS_POST_PROCESSOR_UNITTEST_H_
+
+#include <vector>
+
+#include "chromecast/public/media/audio_post_processor_shlib.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+// This file contains basic tests for AudioPostProcessors.
+// All AudioPostProcessors should run (and pass) the following tests:
+//  TestDelay (tests return value from ProcessFrames)
+//  TestRingingTime (from GetRingingTimeFrames)
+// Additionally, if it is possible to configure the PostProcessor to be a
+// passthrough (no-op), then you should also run
+//  TestPassthrough (tests data in = data out, accounting for delay).
+//
+// Usage:
+// TEST_P(PostProcessorTest, DelayTest) {
+//   std::unique_ptr<AudioPostProcessor> my_post_processor(
+//       AudioPostProcessorShlib_Create(my_config, 2));
+//   TestDelay(my_post_processor, sample_rate_);
+// }
+// (Repeat for TestRingingTime, TestPassthrough).
+//
+// This will run your test with 44100 and 48000 sample rates.
+// You can also make your own tests using the provided helper functions.
+
+namespace chromecast {
+namespace media {
+namespace post_processor_test {
+
+const int kNumChannels = 2;
+
+void TestDelay(AudioPostProcessor* pp, int sample_rate);
+void TestRingingTime(AudioPostProcessor* pp, int sample_rate);
+void TestPassthrough(AudioPostProcessor* pp, int sample_rate);
+
+// Returns the maximum number of frames a PostProcessor may be asked to handle
+// in a single call.
+int GetMaximumFrames(int sample_rate);
+
+// Tests that the first |size| elements of |expected| and |actual| are the same.
+template <typename T>
+void CheckArraysEqual(T* expected, T* actual, size_t size);
+
+// Returns a list of indexes at which |expected| and |actual| differ.
+template <typename T>
+std::vector<int> CompareArray(T* expected, T* actual, size_t size);
+
+// Print the first |size| elemenents of |array| to a string.
+template <typename T>
+std::string ArrayToString(T* array, size_t size);
+
+// Compute the amplitude of a sinusoid as power * sqrt(2)
+// This is more robust that looking for the maximum value.
+template <typename T>
+float SineAmplitude(std::vector<T> data, int num_channels);
+
+// Return a vector of |frames| frames of |kNumChannels| interleaved data.
+// |frequency| is in hz.
+// Channel 0 will be sin(n) and channel 1 will be cos(n).
+std::vector<float> GetSineData(size_t frames, float frequency, int sample_rate);
+
+class PostProcessorTest : public ::testing::TestWithParam<int> {
+ protected:
+  PostProcessorTest();
+  ~PostProcessorTest() override;
+
+  int sample_rate_;
+};
+
+}  // namespace post_processor_test
+}  // namespace media
+}  // namespace chromecast
+
+#endif  // CHROMECAST_MEDIA_CMA_BACKEND_ALSA_POST_PROCESSORS_POST_PROCESSOR_UNITTEST_H_