Send an ack when it 20 packets have been received since the last ack was

net/quic/quic_connection_test.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/quic_connection.h"
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/stl_util.h"
 #include "net/base/net_errors.h"
@@ skipping 1259 matching lines @@
   EXPECT_EQ(3u, writer_->frame_count());
   EXPECT_EQ(1u, writer_->stream_frames().size());
   EXPECT_FALSE(writer_->ack_frames().empty());
 
   // But an ack with no missing packets will not send an ack.
   AckPacket(original, &frame2);
   ProcessAckPacket(&frame2);
   ProcessAckPacket(&frame2);
 }
 
+TEST_P(QuicConnectionTest, 20AcksCausesAckSend) {
+  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
+
+  SendStreamDataToPeer(1, "foo", 0, !kFin, NULL);
+
+  QuicAlarm* ack_alarm = QuicConnectionPeer::GetAckAlarm(&connection_);
+  // But an ack with no missing packets will not send an ack.
+  QuicAckFrame frame = InitAckFrame(1);
+  EXPECT_CALL(*send_algorithm_, OnCongestionEvent(true, _, _, _));
+  EXPECT_CALL(*loss_algorithm_, DetectLostPackets(_, _, _, _))
+      .WillRepeatedly(Return(SequenceNumberSet()));
+  for (int i = 0; i < 20; ++i) {
+    EXPECT_FALSE(ack_alarm->IsSet());
+    ProcessAckPacket(&frame);
+  }
+  EXPECT_TRUE(ack_alarm->IsSet());
+}
+
 TEST_P(QuicConnectionTest, LeastUnackedLower) {
   EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
 
   SendStreamDataToPeer(1, "foo", 0, !kFin, NULL);
   SendStreamDataToPeer(1, "bar", 3, !kFin, NULL);
   SendStreamDataToPeer(1, "eep", 6, !kFin, NULL);
 
   // Start out saying the least unacked is 2.
   peer_creator_.set_sequence_number(5);
   QuicStopWaitingFrame frame = InitStopWaitingFrame(2);
@@ skipping 2586 matching lines @@
   QuicBlockedFrame blocked;
   blocked.stream_id = 3;
   EXPECT_CALL(visitor_, OnBlockedFrames(_));
   ProcessFramePacket(QuicFrame(&blocked));
   EXPECT_TRUE(ack_alarm->IsSet());
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace net