Consistently suggest ephemeral port for QUIC client

net/socket/socket_test_util.cc

Index: net/socket/socket_test_util.cc
diff --git a/net/socket/socket_test_util.cc b/net/socket/socket_test_util.cc
index 148b11c5698927c210c7a8b46b7b0224313b3d03..95b1a38f00950c66627886b6c41032ac2d66c988 100644
--- a/net/socket/socket_test_util.cc
+++ b/net/socket/socket_test_util.cc
@@ -123,6 +123,15 @@ void DumpMockReadWrite(const MockReadWrite<type>& r) {
            << "\nTime:    " << r.time_stamp.ToInternalValue();
 }
 
+void ExerciseSocketRandomNumberGenerator(const RandIntCallback& rand_int_cb) {
+  // Socket connect is supposed to call for some random suggestions for ports.
+  // We call 3 times so that the quic_stream_factory will know this function
+  // was consulted (it has a DCHECK), but will not actually DCHECK the
+  // resulting ephemeral port (which we don't set).
+  for (int count = 3; count > 0; --count)
+    rand_int_cb.Run(1000, 2000);
+}
+
 }  // namespace
 
 MockConnect::MockConnect() : mode(ASYNC), result(OK) {
@@ -663,6 +672,7 @@ MockClientSocketFactory::CreateDatagramClientSocket(
     const RandIntCallback& rand_int_cb,
     net::NetLog* net_log,
     const net::NetLog::Source& source) {
+  ExerciseSocketRandomNumberGenerator(rand_int_cb);

[Ryan Hamilton, 2013/12/08 22:54:15]

Instead of invoking the callback simply to work around, the DCHECK I recommend a
different approach.

* add a port_ member to this class, and initialize it to, say, 123 (which is the
existing port returned by GetLocalAddress).  
* Modify GetLocalAddress to use port_ in the returned value.
* If |bind_type| is RANDOM_BIND, then set port_ to the result of invoking
|rand_int_cb|.

This has the virtue of correctly honoring |bind_type| and makes this method (and
GetLocalAdress) act like the "real" version.

[Ryan Hamilton, 2013/12/09 04:15:50]

I realized that if you make this change, then it should be pretty easy to write
a unit test of QuicStreamFactory that makes two consecutive connections to the
same server and verifies that the same port was used.  You could then make a a
connection to a different server, and verify that the port is different..

   SocketDataProvider* data_provider = mock_data_.GetNext();
   scoped_ptr<MockUDPClientSocket> socket(
       new MockUDPClientSocket(data_provider, net_log));
@@ -1803,6 +1813,7 @@ DeterministicMockClientSocketFactory::CreateDatagramClientSocket(
     const RandIntCallback& rand_int_cb,
     net::NetLog* net_log,
     const NetLog::Source& source) {
+  ExerciseSocketRandomNumberGenerator(rand_int_cb);
   DeterministicSocketData* data_provider = mock_data().GetNext();
   scoped_ptr<DeterministicMockUDPClientSocket> socket(
       new DeterministicMockUDPClientSocket(net_log, data_provider));