Logging basic bad call detection

webrtc/video/quality_threshold_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 "webrtc/video/quality_threshold.h"
+
+#include "webrtc/test/gtest.h"
+
+namespace webrtc {
+
+TEST(QualityThresholdTest, BackAndForth) {
+  QualityThreshold thresh(0, 1, 0.75f, 10);

[sprang_webrtc, 2016/11/24 16:25:21]

Define constants for high / low / capacity and use them below for loop length
and values. 

+  for (int i = 0; i < 8; ++i) {
+    EXPECT_FALSE(thresh.IsHigh());
+    thresh.AddMeasurement(0);
+  }
+  ASSERT_TRUE(thresh.IsHigh());
+  for (int i = 0; i < 8; ++i) {
+    EXPECT_FALSE(*thresh.IsHigh());
+    thresh.AddMeasurement(1);
+  }
+  EXPECT_TRUE(*thresh.IsHigh());
+
+  for (int i = 0; i < 8; ++i) {
+    EXPECT_TRUE(*thresh.IsHigh());
+    thresh.AddMeasurement(0);
+  }
+  EXPECT_FALSE(*thresh.IsHigh());
+}
+
+TEST(QualityThresholdTest, Variance) {
+  const int max_measurements = 10;

[sprang_webrtc, 2016/11/24 16:25:21]

kMaxMeasurements or MAX_MEASUREMENTS

+  const double max_error = 0.01;
+  int values[] = {51, 79, 80, 56, 19, 20, 48, 57, 48, 25, 2, 25, 38, 37, 25};
+  double variances[] = {476.9, 687.6, 552, 336.4, 278.767, 265.167};

[sprang_webrtc, 2016/11/24 16:25:21]

please comment what these numbers are

+  QualityThreshold thresh(0, 1, 0.8f, max_measurements);
+
+  for (int i = 0; i < max_measurements; ++i) {
+    EXPECT_FALSE(thresh.CalculateVariance());
+    thresh.AddMeasurement(values[i]);
+  }
+
+  ASSERT_TRUE(thresh.CalculateVariance());
+  EXPECT_NEAR(variances[0], *thresh.CalculateVariance(), max_error);
+  for (unsigned int i = 1; i < sizeof(variances) / sizeof(double); ++i) {
+    thresh.AddMeasurement(values[i + max_measurements - 1]);
+    EXPECT_NEAR(variances[i], *thresh.CalculateVariance(), max_error);
+  }
+
+  for (int i = 0; i < max_measurements; ++i) {
+    thresh.AddMeasurement(42);
+  }
+  EXPECT_NEAR(0, *thresh.CalculateVariance(), max_error);
+}
+
+TEST(QualityThresholdTest, BetweenThresholds) {
+  const int max_measurements = 10;
+  QualityThreshold thresh(0, 2, 0.6f, max_measurements);
+  for (int i = 0; i < 2 * max_measurements; ++i) {
+    EXPECT_FALSE(thresh.IsHigh());
+    thresh.AddMeasurement(1);
+  }
+  EXPECT_FALSE(thresh.IsHigh());
+}
+
+}  // namespace webrtc