Added implementation of three classes in BBR,with unit-tests.

webrtc/modules/remote_bitrate_estimator/test/estimators/congestion_window_unittest.cc

Index: webrtc/modules/remote_bitrate_estimator/test/estimators/congestion_window_unittest.cc
diff --git a/webrtc/modules/remote_bitrate_estimator/test/estimators/congestion_window_unittest.cc b/webrtc/modules/remote_bitrate_estimator/test/estimators/congestion_window_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a2d50dfe9e2c7023c34c12cedc1142c63f0d4d20
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+++ b/webrtc/modules/remote_bitrate_estimator/test/estimators/congestion_window_unittest.cc
@@ -0,0 +1,82 @@
+/*
+ *  Copyright (c) 2017 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/modules/remote_bitrate_estimator/test/estimators/congestion_window.h"
+#include "webrtc/modules/remote_bitrate_estimator/test/estimators/bbr.h"
+
+#include "webrtc/test/gtest.h"
+
+namespace webrtc {
+namespace testing {
+namespace bwe {
+namespace {
+// These are the same values used in CongestionWindow class.
+const int64_t kStartingCongestionWindow = 6000;
+const int64_t kMinimumCongestionWindow = 5840;
+}  // namespace
+
+TEST(CongestionWindowTest, InitializationCheck) {
+  CongestionWindow congestion_window;
+  congestion_window.PacketSent(0);
+  EXPECT_EQ(congestion_window.data_inflight(), 0u);
+  congestion_window.AckReceived(0);
+  EXPECT_EQ(congestion_window.data_inflight(), 0u);
+}
+
+TEST(CongestionWindowTest, DataInflight) {
+  CongestionWindow congestion_window;
+  congestion_window.PacketSent(13);
+  EXPECT_EQ(congestion_window.data_inflight(), 13u);
+  congestion_window.AckReceived(12);
+  EXPECT_EQ(congestion_window.data_inflight(), 1u);
+  congestion_window.PacketSent(10);
+  congestion_window.PacketSent(9);
+  EXPECT_EQ(congestion_window.data_inflight(), 20u);
+  congestion_window.AckReceived(20);
+  EXPECT_EQ(congestion_window.data_inflight(), 0u);
+}
+
+TEST(CongestionWindowTest, ZeroBandwidthDelayProduct) {
+  CongestionWindow congestion_window;
+  int64_t target_congestion_window =
+      congestion_window.GetTargetCongestionWindow(100, 0, 2.885);
+  EXPECT_EQ(target_congestion_window, 2.885 * kStartingCongestionWindow);
+}
+
+TEST(CongestionWindowTest, BelowMinimumTargetCongestionWindow) {
+  CongestionWindow congestion_window;
+  int64_t target_congestion_window =
+      congestion_window.GetTargetCongestionWindow(100, 2, 2.885);
+  EXPECT_EQ(target_congestion_window, kMinimumCongestionWindow);
+}
+
+TEST(CongestionWindowTest, AboveMinimumTargetCongestionWindow) {
+  CongestionWindow congestion_window;
+  int64_t target_congestion_window =
+      congestion_window.GetTargetCongestionWindow(100000, 2, 2.885);
+  EXPECT_EQ(target_congestion_window, 577000);
+}
+
+TEST(CongestionWindowTest, MinimumCongestionWindow) {
+  CongestionWindow congestion_window;
+  int64_t cwnd = congestion_window.GetCongestionWindow(BbrBweSender::PROBE_RTT,
+                                                       100, 100, 2.885f);
+  EXPECT_EQ(cwnd, kMinimumCongestionWindow);
+}
+
+TEST(CongestionWindowTest, CalculateCongestionWindow) {
+  CongestionWindow congestion_window;
+  int64_t cwnd = congestion_window.GetCongestionWindow(BbrBweSender::STARTUP,
+                                                       100, 100, 2.885f);
+  EXPECT_EQ(cwnd, 28850);
+}
+}  // namespace bwe
+}  // namespace testing
+}  // namespace webrtc