Display isolate message queue in Observatory debugger

runtime/vm/service_test.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 
 #include "include/dart_debugger_api.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
@@ skipping 488 matching lines @@
   service_msg = Eval(lib, "[0, port, '0', 'alpha', [], []]");
   Service::HandleRootMessage(service_msg);
   handler.HandleNextMessage();
   EXPECT_STREQ("{\"result\":alpha, \"id\":\"0\"}", handler.msg());
   service_msg = Eval(lib, "[0, port, '0', 'beta', [], []]");
   Service::HandleRootMessage(service_msg);
   handler.HandleNextMessage();
   EXPECT_STREQ("{\"result\":beta, \"id\":\"0\"}", handler.msg());
 }
 
+
 TEST_CASE(Service_EmbedderIsolateHandler) {
   const char* kScript =
     "var port;\n"  // Set to our mock port by C++.
     "\n"
     "var x = 7;\n"
     "main() {\n"
     "  x = x * x;\n"
     "  x = x / 13;\n"
     "}";
 
@@ skipping 18 matching lines @@
   Service::HandleIsolateMessage(isolate, service_msg);
   handler.HandleNextMessage();
   EXPECT_STREQ("{\"result\":alpha, \"id\":\"0\"}", handler.msg());
   service_msg = Eval(lib, "[0, port, '0', 'beta', [], []]");
   Service::HandleIsolateMessage(isolate, service_msg);
   handler.HandleNextMessage();
   EXPECT_STREQ("{\"result\":beta, \"id\":\"0\"}", handler.msg());
 }
 
 
+static uint8_t* AllocMsg(const char* str) {
+  return reinterpret_cast<uint8_t*>(strdup(str));
+}
+
+
+TEST_CASE(Service_MessageQueue) {
+  MessageQueue queue;
+  EXPECT(queue.IsEmpty());
+
+  Dart_Port port = 1;
+
+  const char* str1 = "msg1";
+
+  // Add a message.
+  Message* msg1 = new Message(
+      port, AllocMsg(str1), strlen(str1) + 1, Message::kNormalPriority);
+  queue.Enqueue(msg1, false);
+  EXPECT(queue.Length() == 1);
+  EXPECT(!queue.IsEmpty());
+
+  // Print MessageQueue to JSON.
+  JSONStream stream;
+  queue.PrintJSON(&stream);
+  // Expect a Message type.
+  EXPECT_SUBSTRING("\"type\":\"Message\"", stream.ToCString());
+}
+
 // TODO(zra): Remove when tests are ready to enable.
 #if !defined(TARGET_ARCH_ARM64)
 
 TEST_CASE(Service_Profile) {
   const char* kScript =
       "var port;\n"  // Set to our mock port by C++.
       "\n"
       "var x = 7;\n"
       "main() {\n"
       "  x = x * x;\n"
@@ skipping 31 matching lines @@
       Eval(lib, "[0, port, '0', 'getCpuProfile', ['tags'], ['Bogus']]");
   Service::HandleIsolateMessage(isolate, service_msg);
   handler.HandleNextMessage();
   // Expect error.
   EXPECT_SUBSTRING("\"type\":\"Error\"", handler.msg());
 }
 
 #endif  // !defined(TARGET_ARCH_ARM64)
 
 }  // namespace dart