[Sync] Store the past 10 traffic records in memory.

sync/engine/traffic_recorder_unittest.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 "sync/engine/traffic_recorder.h"
+
+#include "sync/protocol/sync.pb.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace browser_sync {
+
+extern const unsigned int kMaxMessages;

[akalin, 2012/03/27 23:53:44]

eh, this is pretty gross. :/ Make TrafficRecorder's constructor take these as
parameters, and move the constants in SyncSession or something.  Then you can
test with some constants for test purposes.

also, why would you need to re-declare these again here if you're including the
header file (which has these declarations)?

[lipalani1, 2012/03/29 00:23:13]

Done.

+extern const unsigned int kMaxMessageSize;
+
+// Ensure the number of records don't exceed |kMaxMessages|.
+TEST(TrafficRecorderTest, MaxRecordsTest) {
+  TrafficRecorder recorder;
+  TrafficRecorder::TrafficRecord record;
+
+  for (unsigned int i = 0; i<2*kMaxMessages; ++i)

[akalin, 2012/03/27 23:53:44]

prefer calling the public interface

[lipalani1, 2012/03/29 00:23:13]

Done.

+    recorder.AddTrafficToQueue(record);
+
+  EXPECT_EQ(recorder.records_.size(), kMaxMessages);
+}
+
+// Ensure records with size greater than |kMaxMessageSize| are truncated.
+TEST(TrafficRecorderTest, MaxMessageSizeTest) {
+  sync_pb::ClientToServerResponse response;
+
+  int id = 0;
+  while ((unsigned int)response.ByteSize() < kMaxMessageSize) {

[akalin, 2012/03/27 23:53:44]

you can just assign to error_message some large string

[lipalani1, 2012/03/29 00:23:13]

hmm... I dont want to type in a large error message. This seems easier.
On 2012/03/27 23:53:44, akalin wrote:

[akalin, 2012/03/29 08:13:14]

You don't have to literally type in the large error message.  You can just do:

std::string foo(kMaxMessageSize);

and it'll initialize a string of that size.

+    response.add_migrated_data_type_id(id);
+    ++id;
+  }
+
+  TrafficRecorder recorder;
+  recorder.RecordClientToServerResponse(response);
+
+  TrafficRecorder::TrafficRecord record = recorder.records_.front();
+  EXPECT_TRUE(record.truncated);
+  EXPECT_TRUE(record.message.empty());
+}
+
+}  //namespace browser_sync