1 files changed, 103 insertions, 0 deletions
diff --git a/third_party/libwebrtc/common_video/frame_rate_estimator_unittest.cc b/third_party/libwebrtc/common_video/frame_rate_estimator_unittest.cc
new file mode 100644
index 0000000000..d11a7d4140
--- /dev/null
+++ b/third_party/libwebrtc/common_video/frame_rate_estimator_unittest.cc
@@ -0,0 +1,103 @@
+/*
+ *  Copyright (c) 2019 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 "common_video/frame_rate_estimator.h"
+
+#include "system_wrappers/include/clock.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
+
+namespace webrtc {
+namespace {
+constexpr TimeDelta kDefaultWindow = TimeDelta::Millis(1000);
+}
+
+class FrameRateEstimatorTest : public ::testing::Test {
+ public:
+  FrameRateEstimatorTest() : clock_(123), estimator_(kDefaultWindow) {}
+
+ protected:
+  SimulatedClock clock_;
+  FrameRateEstimator estimator_;
+};
+
+TEST_F(FrameRateEstimatorTest, NoEstimateWithLessThanTwoFrames) {
+  EXPECT_FALSE(estimator_.GetAverageFps());
+  estimator_.OnFrame(clock_.CurrentTime());
+  EXPECT_FALSE(estimator_.GetAverageFps());
+  clock_.AdvanceTime(TimeDelta::Millis(33));
+  EXPECT_FALSE(estimator_.GetAverageFps());
+}
+
+TEST_F(FrameRateEstimatorTest, NoEstimateWithZeroSpan) {
+  // Two frames, but they are spanning 0ms so can't estimate frame rate.
+  estimator_.OnFrame(clock_.CurrentTime());
+  estimator_.OnFrame(clock_.CurrentTime());
+  EXPECT_FALSE(estimator_.GetAverageFps());
+}
+
+TEST_F(FrameRateEstimatorTest, SingleSpanFps) {
+  const double kExpectedFps = 30.0;
+  estimator_.OnFrame(clock_.CurrentTime());
+  clock_.AdvanceTime(TimeDelta::Seconds(1) / kExpectedFps);
+  estimator_.OnFrame(clock_.CurrentTime());
+  EXPECT_NEAR(*estimator_.GetAverageFps(), kExpectedFps, 0.001);
+}
+
+TEST_F(FrameRateEstimatorTest, AverageFps) {
+  // Insert frames a intervals corresponding to 10fps for half the window, then
+  // 40fps half the window. The average should be 20fps.
+  const double kLowFps = 10.0;
+  const double kHighFps = 30.0;
+  const double kExpectedFps = 20.0;
+
+  const Timestamp start_time = clock_.CurrentTime();
+  while (clock_.CurrentTime() - start_time < kDefaultWindow / 2) {
+    estimator_.OnFrame(clock_.CurrentTime());
+    clock_.AdvanceTime(TimeDelta::Seconds(1) / kLowFps);
+  }
+  while (clock_.CurrentTime() - start_time < kDefaultWindow) {
+    estimator_.OnFrame(clock_.CurrentTime());
+    clock_.AdvanceTime(TimeDelta::Seconds(1) / kHighFps);
+  }
+
+  EXPECT_NEAR(*estimator_.GetAverageFps(), kExpectedFps, 0.001);
+}
+
+TEST_F(FrameRateEstimatorTest, CullsOldFramesFromAveragingWindow) {
+  // Two frames, just on the border of the 1s window => 1 fps.
+  estimator_.OnFrame(clock_.CurrentTime());
+  clock_.AdvanceTime(kDefaultWindow);
+  estimator_.OnFrame(clock_.CurrentTime());
+  EXPECT_TRUE(estimator_.GetAverageFps());
+  EXPECT_NEAR(*estimator_.GetAverageFps(), 1.0, 0.001);
+
+  // Oldest frame should just be pushed out the window, leaving a single frame
+  // => no estimate possible.
+  clock_.AdvanceTime(TimeDelta::Micros(1));
+  EXPECT_FALSE(estimator_.GetAverageFps(clock_.CurrentTime()));
+}
+
+TEST_F(FrameRateEstimatorTest, Reset) {
+  estimator_.OnFrame(clock_.CurrentTime());
+  clock_.AdvanceTime(TimeDelta::Seconds(1) / 30);
+  estimator_.OnFrame(clock_.CurrentTime());
+  EXPECT_TRUE(estimator_.GetAverageFps());
+
+  // Clear estimator, no estimate should be possible even after inserting one
+  // new frame.
+  estimator_.Reset();
+  EXPECT_FALSE(estimator_.GetAverageFps());
+  clock_.AdvanceTime(TimeDelta::Seconds(1) / 30);
+  estimator_.OnFrame(clock_.CurrentTime());
+  EXPECT_FALSE(estimator_.GetAverageFps());
+}
+
+}  // namespace webrtc