Adds a modified copy of talk/base to webrtc/base. It is the first step in migrating talk/base to webrtc/base.

BUG=N/A
R=andrew@webrtc.org, wu@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/12199004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6107 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/base/ratetracker_unittest.cc

@@ -0,0 +1,74 @@
+/*
+ *  Copyright 2010 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/base/gunit.h"
+#include "webrtc/base/ratetracker.h"
+
+namespace rtc {
+
+class RateTrackerForTest : public RateTracker {
+ public:
+  RateTrackerForTest() : time_(0) {}
+  virtual uint32 Time() const { return time_; }
+  void AdvanceTime(uint32 delta) { time_ += delta; }
+
+ private:
+  uint32 time_;
+};
+
+TEST(RateTrackerTest, TestBasics) {
+  RateTrackerForTest tracker;
+  EXPECT_EQ(0U, tracker.total_units());
+  EXPECT_EQ(0U, tracker.units_second());
+
+  // Add a sample.
+  tracker.Update(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());
+
+  // Repeat.
+  tracker.Update(1234);
+  tracker.AdvanceTime(100);
+  EXPECT_EQ(1234U * 2, tracker.total_units());
+  EXPECT_EQ(0U, tracker.units_second());
+
+  // 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());
+
+  // 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());
+
+  // 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());
+
+  // 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.AdvanceTime(100);
+  }
+  EXPECT_EQ(9876U * 10, tracker.units_second());
+
+  // 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());
+}
+
+}  // namespace rtc