Trace the stats report as JSON instead of each stat separately.

webrtc/pc/rtcstats_integrationtest.cc

 /*
  *  Copyright 2016 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 <set>
 #include <vector>
 
 #include "webrtc/api/audio_codecs/builtin_audio_decoder_factory.h"
 #include "webrtc/api/audio_codecs/builtin_audio_encoder_factory.h"
 #include "webrtc/api/datachannelinterface.h"
 #include "webrtc/api/peerconnectioninterface.h"
 #include "webrtc/api/stats/rtcstats_objects.h"
 #include "webrtc/api/stats/rtcstatsreport.h"
 #include "webrtc/pc/test/peerconnectiontestwrapper.h"
 #include "webrtc/pc/test/rtcstatsobtainer.h"
 #include "webrtc/rtc_base/checks.h"
 #include "webrtc/rtc_base/event_tracer.h"
 #include "webrtc/rtc_base/gunit.h"
 #include "webrtc/rtc_base/refcountedobject.h"
 #include "webrtc/rtc_base/scoped_ref_ptr.h"
+#include "webrtc/rtc_base/trace_event.h"
 #include "webrtc/rtc_base/virtualsocketserver.h"
 
 namespace webrtc {
 
 namespace {
 
 const int64_t kGetStatsTimeoutMs = 10000;
 
 const unsigned char* GetCategoryEnabledHandler(const char* name) {
-  return reinterpret_cast<const unsigned char*>("webrtc_stats");
+  if (strcmp("webrtc_stats", name) != 0) {
+    return reinterpret_cast<const unsigned char*>("");
+  }
+  return reinterpret_cast<const unsigned char*>(name);
 }
 
-void AddTraceEventHandler(char phase,
-                          const unsigned char* category_enabled,
-                          const char* name,
-                          unsigned long long id,
-                          int num_args,
-                          const char** arg_names,
-                          const unsigned char* arg_types,
-                          const unsigned long long* arg_values,
-                          unsigned char flags) {
-  // Do nothing
-}
+class RTCStatsTracedReport {

[hbos, 2017/08/14 15:49:23]

nit: Maybe RTCStatsReportTraceListener is a more suitable name?

[ehmaldonado_webrtc, 2017/08/14 16:14:07]

Agree. Done.

+ public:
+  static void SetUp() {
+    if (!traced_report_)
+      traced_report_ = new RTCStatsTracedReport();
+    traced_report_->last_trace_ = "";
+    SetupEventTracer(&GetCategoryEnabledHandler,
+                     &RTCStatsTracedReport::AddTraceEventHandler);
+  }
+
+  static std::string& GetTracedReport() {

[hbos, 2017/08/14 15:49:23]

nit: const std::string& last_trace()

[ehmaldonado_webrtc, 2017/08/14 16:14:07]

Done.

+    RTC_DCHECK(traced_report_);
+    return traced_report_->last_trace_;
+  }
+
+ private:
+  static void AddTraceEventHandler(char phase,
+                                   const unsigned char* category_enabled,
+                                   const char* name,
+                                   unsigned long long id,
+                                   int num_args,
+                                   const char** arg_names,
+                                   const unsigned char* arg_types,
+                                   const unsigned long long* arg_values,
+                                   unsigned char flags) {
+    RTC_DCHECK(traced_report_);
+    EXPECT_EQ(traced_report_->last_trace_, "");
+    EXPECT_STREQ("webrtc_stats",
+                 reinterpret_cast<const char*>(category_enabled));
+    EXPECT_STREQ("webrtc_stats", name);
+    EXPECT_EQ(1, num_args);
+    EXPECT_STREQ("report", arg_names[0]);
+    EXPECT_EQ(TRACE_VALUE_TYPE_COPY_STRING, arg_types[0]);
+
+    traced_report_->last_trace_ =
+        reinterpret_cast<const char*>(arg_values[0]);
+  }
+
+  std::string last_trace_;
+  static RTCStatsTracedReport* traced_report_;

[hbos, 2017/08/14 15:49:23]

nit: Can't find anything in the style guide, but I would guess static member
variable goes before non-static member variables.

[ehmaldonado_webrtc, 2017/08/14 16:14:07]

Done.

+};
+
+RTCStatsTracedReport* RTCStatsTracedReport::traced_report_ = nullptr;
 
 class RTCStatsIntegrationTest : public testing::Test {
  public:
   RTCStatsIntegrationTest()
       : network_thread_(new rtc::Thread(&virtual_socket_server_)),
         worker_thread_(rtc::Thread::Create()) {
-    SetupEventTracer(&GetCategoryEnabledHandler, &AddTraceEventHandler);
+    RTCStatsTracedReport::SetUp();
 
     RTC_CHECK(network_thread_->Start());
     RTC_CHECK(worker_thread_->Start());
 
     caller_ = new rtc::RefCountedObject<PeerConnectionTestWrapper>(
         "caller", network_thread_.get(), worker_thread_.get());
     callee_ = new rtc::RefCountedObject<PeerConnectionTestWrapper>(
         "callee", network_thread_.get(), worker_thread_.get());
   }
 
@@ skipping 576 matching lines @@
  private:
   rtc::scoped_refptr<const RTCStatsReport> report_;
 };
 
 #ifdef HAVE_SCTP
 TEST_F(RTCStatsIntegrationTest, GetStatsFromCaller) {
   StartCall();
 
   rtc::scoped_refptr<const RTCStatsReport> report = GetStatsFromCaller();
   RTCStatsReportVerifier(report.get()).VerifyReport();
+  EXPECT_EQ(report->ToJson(), RTCStatsTracedReport::GetTracedReport());
 }
 
 TEST_F(RTCStatsIntegrationTest, GetStatsFromCallee) {
   StartCall();
 
   rtc::scoped_refptr<const RTCStatsReport> report = GetStatsFromCallee();
   RTCStatsReportVerifier(report.get()).VerifyReport();
+  EXPECT_EQ(report->ToJson(), RTCStatsTracedReport::GetTracedReport());
 }
 
 TEST_F(RTCStatsIntegrationTest, GetsStatsWhileDestroyingPeerConnections) {
   StartCall();
 
   rtc::scoped_refptr<RTCStatsObtainer> stats_obtainer =
       RTCStatsObtainer::Create();
   caller_->pc()->GetStats(stats_obtainer);
   // This will destroy the peer connection.
   caller_ = nullptr;
   // Any pending stats requests should have completed in the act of destroying
   // the peer connection.
   EXPECT_TRUE(stats_obtainer->report());
+  EXPECT_EQ(stats_obtainer->report()->ToJson(),
+            RTCStatsTracedReport::GetTracedReport());
 }
 #endif  // HAVE_SCTP
 
 }  // namespace
 
 }  // namespace webrtc