[rtp_rtcp] RTT intermidiate calculation use ntp time instead of milliseconds.

webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl_unittest.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl_unittest.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl_unittest.cc b/webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl_unittest.cc
index 8329f603f9221feaebfb1cf5d5b372602edb2137..c6936957929b0b39537b70b6893266fe5fddd270 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl_unittest.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl_unittest.cc
@@ -309,10 +309,10 @@ TEST_F(RtpRtcpImplTest, Rtt) {
   int64_t max_rtt;
   EXPECT_EQ(0,
       sender_.impl_->RTT(kReceiverSsrc, &rtt, &avg_rtt, &min_rtt, &max_rtt));
-  EXPECT_EQ(2 * kOneWayNetworkDelayMs, rtt);
-  EXPECT_EQ(2 * kOneWayNetworkDelayMs, avg_rtt);
-  EXPECT_EQ(2 * kOneWayNetworkDelayMs, min_rtt);
-  EXPECT_EQ(2 * kOneWayNetworkDelayMs, max_rtt);
+  EXPECT_NEAR(2 * kOneWayNetworkDelayMs, rtt, 1);
+  EXPECT_NEAR(2 * kOneWayNetworkDelayMs, avg_rtt, 1);
+  EXPECT_NEAR(2 * kOneWayNetworkDelayMs, min_rtt, 1);
+  EXPECT_NEAR(2 * kOneWayNetworkDelayMs, max_rtt, 1);
 
   // No RTT from other ssrc.
   EXPECT_EQ(-1,
@@ -322,8 +322,9 @@ TEST_F(RtpRtcpImplTest, Rtt) {
   EXPECT_EQ(0, sender_.rtt_stats_.LastProcessedRtt());
   EXPECT_EQ(0, sender_.impl_->rtt_ms());
   sender_.impl_->Process();
-  EXPECT_EQ(2 * kOneWayNetworkDelayMs, sender_.rtt_stats_.LastProcessedRtt());
-  EXPECT_EQ(2 * kOneWayNetworkDelayMs, sender_.impl_->rtt_ms());
+  EXPECT_NEAR(2 * kOneWayNetworkDelayMs, sender_.rtt_stats_.LastProcessedRtt(),
+              1);
+  EXPECT_NEAR(2 * kOneWayNetworkDelayMs, sender_.impl_->rtt_ms(), 1);
 }
 
 TEST_F(RtpRtcpImplTest, SetRtcpXrRrtrStatus) {
@@ -346,8 +347,9 @@ TEST_F(RtpRtcpImplTest, RttForReceiverOnly) {
   EXPECT_EQ(0, receiver_.rtt_stats_.LastProcessedRtt());
   EXPECT_EQ(0, receiver_.impl_->rtt_ms());
   receiver_.impl_->Process();
-  EXPECT_EQ(2 * kOneWayNetworkDelayMs, receiver_.rtt_stats_.LastProcessedRtt());
-  EXPECT_EQ(2 * kOneWayNetworkDelayMs, receiver_.impl_->rtt_ms());
+  EXPECT_NEAR(2 * kOneWayNetworkDelayMs,
+              receiver_.rtt_stats_.LastProcessedRtt(), 1);
+  EXPECT_NEAR(2 * kOneWayNetworkDelayMs, receiver_.impl_->rtt_ms(), 1);

[stefan-webrtc, 2016/02/03 10:03:11]

Here too, it'd be nice to know why this isn't as exact any longer?

[danilchap, 2016/02/03 13:27:11]

It wasn't exact before too, but with simulated clock using milliseconds it was
more likely answer would be exact.
It is possible to increase chance to get exact rtt in tests by changing Rounding
from 'round down' to 'round to nearest'. Or pick different values to get exact
values, but I think it is better to show in tests that RTT can't be estimated
exactly.

 }
 
 TEST_F(RtpRtcpImplTest, NoSrBeforeMedia) {