Add test case for custom error's toString.

test/cctest/test-api.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3038 matching lines @@
   CHECK(string->Equals(v8_str("Whoops")));
   CompileRun("ReferenceError.prototype.constructor = new Object();"
              "ReferenceError.prototype.constructor.name = 1;"
              "Number.prototype.toString = function() { return 'Whoops'; };"
              "ReferenceError.prototype.toString = Object.prototype.toString;");
   CompileRun("asdf;");
   v8::V8::RemoveMessageListeners(check_message);
 }
 
 
+static void check_custom_error_message(
+    v8::Handle<v8::Message> message,
+    v8::Handle<v8::Value> data) {
+  const char* uncaught_error = "Uncaught MyError toString";
+  CHECK(message->Get()->Equals(v8_str(uncaught_error)));
+}
+
+
+TEST(CustomErrorToString) {
+  v8::HandleScope scope;
+  v8::V8::AddMessageListener(check_custom_error_message);
+  LocalContext context;
+  CompileRun(
+    "function MyError(name, message) {                   "
+    "  this.name = name;                                 "
+    "  this.message = message;                           "
+    "}                                                   "
+    "MyError.prototype = Object.create(Error.prototype); "
+    "MyError.prototype.toString = function() {           "
+    "  return 'MyError toString';                        "
+    "};                                                  "
+    "throw new MyError('my name', 'my message');         ");
+  v8::V8::RemoveMessageListeners(check_custom_error_message);
+}
+
+
 static void receive_message(v8::Handle<v8::Message> message,
                             v8::Handle<v8::Value> data) {
   message->Get();
   message_received = true;
 }
 
 
 TEST(APIThrowMessage) {
   message_received = false;
   v8::HandleScope scope;
@@ skipping 13759 matching lines @@
         "  x++;                      \n"
         "  throw new Error('again'); \n"  // This is the new uncaught error.
         "}                           \n";
     CompileRun(throw_again);
     CHECK(try_catch.HasCaught());
     Local<Message> message = try_catch.Message();
     CHECK(!message.IsEmpty());
     CHECK_EQ(6, message->GetLineNumber());
   }
 }