Add a rate tracker that tracks rate over a given interval split up into buckets that accumulate uni…

webrtc/base/ratetracker_unittest.cc

Index: webrtc/base/ratetracker_unittest.cc
diff --git a/webrtc/base/ratetracker_unittest.cc b/webrtc/base/ratetracker_unittest.cc
index 1c20fd05a2732c7e14e61713fbe3da6d645f5bd5..f0a3a9675f40a4f1aa939743e2e47a297100adb4 100644
--- a/webrtc/base/ratetracker_unittest.cc
+++ b/webrtc/base/ratetracker_unittest.cc
@@ -1,5 +1,5 @@
 /*
- *  Copyright 2010 The WebRTC Project Authors. All rights reserved.
+ *  Copyright 2015 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
@@ -15,7 +15,7 @@ namespace rtc {
 
 class RateTrackerForTest : public RateTracker {
  public:
-  RateTrackerForTest() : time_(0) {}
+  RateTrackerForTest() : RateTracker(100u, 10u), time_(0) {}
   virtual uint32 Time() const { return time_; }
   void AdvanceTime(uint32 delta) { time_ += delta; }
 
@@ -23,59 +23,102 @@ class RateTrackerForTest : public RateTracker {
   uint32 time_;
 };
 
-TEST(RateTrackerTest, TestBasics) {
+TEST(RateTrackerTest, Test30FPS) {
   RateTrackerForTest tracker;
-  EXPECT_EQ(0U, tracker.total_units());
-  EXPECT_EQ(0U, tracker.units_second());
+
+  for (int i = 0; i < 300; ++i) {
+    tracker.AddSamples(1);
+    tracker.AdvanceTime(33);
+    if (i % 3 == 0) {
+      tracker.AdvanceTime(1);
+    }
+  }
+  EXPECT_EQ(30u, tracker.ComputeCurrentRate(50000u));

[noahric, 2015/09/03 21:42:24]

Is there a version of this for doubles/floats that does equality comparison with
an epsilon?

I'm actually surprised this doesn't fail on windows trybots, which has
occasionally more strict signed/unsigned checking.

[tpsiaki, 2015/09/03 23:28:59]

Done.

+}
+
+TEST(RateTrackerTest, Test60FPS) {
+  RateTrackerForTest tracker;
+
+  for (int i = 0; i < 300; ++i) {
+    tracker.AddSamples(1);
+    tracker.AdvanceTime(16);
+    if (i % 3 != 0) {
+      tracker.AdvanceTime(1);
+    }
+  }
+  EXPECT_EQ(60u, tracker.ComputeCurrentRate(1000u));
+}
+
+TEST(RateTrackerTest, TestRateTrackerBasics) {
+  RateTrackerForTest tracker;
+  EXPECT_EQ(0U, tracker.ComputeCurrentRate(1000u));
 
   // Add a sample.
-  tracker.Update(1234);
+  tracker.AddSamples(1234);
   // Advance the clock by 100 ms.
   tracker.AdvanceTime(100);
-  // total_units should advance, but units_second should stay 0.
-  EXPECT_EQ(1234U, tracker.total_units());
-  EXPECT_EQ(0U, tracker.units_second());
+  EXPECT_EQ(12340U, tracker.ComputeCurrentRate(1000u));
+  EXPECT_EQ(12340U, tracker.ComputeCurrentRate());
+  EXPECT_EQ(1234U, tracker.TotalSampleCount());
+  EXPECT_EQ(12340U, tracker.ComputeTotalRate());
 
   // Repeat.
-  tracker.Update(1234);
+  tracker.AddSamples(1234);
   tracker.AdvanceTime(100);
-  EXPECT_EQ(1234U * 2, tracker.total_units());
-  EXPECT_EQ(0U, tracker.units_second());
+  EXPECT_EQ(12340U, tracker.ComputeCurrentRate(1000u));
+  EXPECT_EQ(12340U, tracker.ComputeCurrentRate());
+  EXPECT_EQ(1234U * 2, tracker.TotalSampleCount());
+  EXPECT_EQ(12340U, tracker.ComputeTotalRate());
 
   // Advance the clock by 800 ms, so we've elapsed a full second.
   // units_second should now be filled in properly.
   tracker.AdvanceTime(800);
-  EXPECT_EQ(1234U * 2, tracker.total_units());
-  EXPECT_EQ(1234U * 2, tracker.units_second());
+  EXPECT_EQ(1234U * 2, tracker.ComputeCurrentRate(1000u));
+  EXPECT_EQ(1234U * 2, tracker.ComputeCurrentRate());
+  EXPECT_EQ(1234U * 2, tracker.TotalSampleCount());
+  EXPECT_EQ(1234U * 2, tracker.ComputeTotalRate());
 
   // Poll the tracker again immediately. The reported rate should stay the same.
-  EXPECT_EQ(1234U * 2, tracker.total_units());
-  EXPECT_EQ(1234U * 2, tracker.units_second());
+  EXPECT_EQ(1234U * 2, tracker.ComputeCurrentRate(1000u));
+  EXPECT_EQ(1234U * 2, tracker.ComputeCurrentRate());
+  EXPECT_EQ(1234U * 2, tracker.TotalSampleCount());
+  EXPECT_EQ(1234U * 2, tracker.ComputeTotalRate());
 
   // Do nothing and advance by a second. We should drop down to zero.
   tracker.AdvanceTime(1000);
-  EXPECT_EQ(1234U * 2, tracker.total_units());
-  EXPECT_EQ(0U, tracker.units_second());
+  EXPECT_EQ(0U, tracker.ComputeCurrentRate(1000u));
+  EXPECT_EQ(0U, tracker.ComputeCurrentRate());
+  EXPECT_EQ(1234U * 2, tracker.TotalSampleCount());
+  EXPECT_EQ(1234U, tracker.ComputeTotalRate());
 
   // Send a bunch of data at a constant rate for 5.5 "seconds".
   // We should report the rate properly.
   for (int i = 0; i < 5500; i += 100) {
-    tracker.Update(9876U);
+    tracker.AddSamples(9876U);
     tracker.AdvanceTime(100);
   }
-  EXPECT_EQ(9876U * 10, tracker.units_second());
+  EXPECT_EQ(9876U * 10, tracker.ComputeCurrentRate(1000u));
+  EXPECT_EQ(9876U * 10, tracker.ComputeCurrentRate());
+  EXPECT_EQ(1234U * 2 + 9876U * 55, tracker.TotalSampleCount());
+  EXPECT_EQ((1234U * 2 + 9876U * 55) / 7.5, tracker.ComputeTotalRate());
 
   // Advance the clock by 500 ms. Since we sent nothing over this half-second,
   // the reported rate should be reduced by half.
   tracker.AdvanceTime(500);
-  EXPECT_EQ(9876U * 5, tracker.units_second());
+  EXPECT_EQ(9876U * 5, tracker.ComputeCurrentRate(1000u));
+  EXPECT_EQ(9876U * 5, tracker.ComputeCurrentRate());
+  EXPECT_EQ(1234U * 2 + 9876U * 55, tracker.TotalSampleCount());
+  EXPECT_EQ((1234U * 2 + 9876U * 55) / 8.0, tracker.ComputeTotalRate());
+
+  // Rate over the last half second should be zero.
+  EXPECT_EQ(0u, tracker.ComputeCurrentRate(500u));

[noahric, 2015/09/03 21:42:24]

Can you also test (1) elapsed time > number of buckets and (2) more 
explicit roll-off testing, e.g. fill with 10fps, check 10fps; half-fill with
20fps (so half the 10 rolled off), check 15fps; half-fill rest of 20fps, check
20fps

Or, for (2) put another way, tests in which ComputeCurrentRate(arg) !=
ComputeCurrentRate().

[tpsiaki, 2015/09/03 23:28:59]

Done.

 }
 
 TEST(RateTrackerTest, TestGetUnitSecondsAfterInitialValue) {
   RateTrackerForTest tracker;
-  tracker.Update(1234);
+  tracker.AddSamples(1234);
   tracker.AdvanceTime(1000);
-  EXPECT_EQ(1234u, tracker.units_second());
+  EXPECT_EQ(1234u, tracker.ComputeCurrentRate(1000u));
 }
 
 }  // namespace rtc