Add more unit tests for JS bindings to Core

mojo/public/bindings/js/test/harness.cc

 // Copyright 2013 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 "base/file_util.h"
 #include "base/path_service.h"
 #include "gin/converter.h"
 #include "gin/runner.h"
 #include "gin/test/gtest.h"
 #include "mojo/public/bindings/js/runner_delegate.h"
@@ skipping 14 matching lines @@
 
   virtual v8::Handle<Object> CreateRootObject(
       gin::Runner* runner) MOJO_OVERRIDE {
     v8::Handle<Object> root = RunnerDelegate::CreateRootObject(runner);
     root->Set(gin::StringToSymbol(runner->isolate(), "gtest"),
               gin::GetGTestTemplate(runner->isolate())->NewInstance());
     return root;
   }
 };
 
+std::string GetExceptionInfo(const v8::TryCatch& try_catch) {
+  std::string info;
+  gin::ConvertFromV8(try_catch.Message()->Get(), &info);
+  return info;
+}
+
 void RunTestFromFile(const base::FilePath& path) {
   EXPECT_TRUE(base::PathExists(path)) << path.LossyDisplayName();
   std::string source;
   EXPECT_TRUE(ReadFileToString(path, &source));
   Isolate* isolate = Isolate::GetCurrent();
 
   TestRunnerDelegate delegate;
   gin::Runner runner(&delegate, isolate);
   gin::Runner::Scope scope(&runner);
 
   v8::TryCatch try_catch;
   runner.Run(Script::New(gin::StringToV8(isolate, source)));
 
-  EXPECT_FALSE(try_catch.HasCaught());
+  EXPECT_FALSE(try_catch.HasCaught()) << GetExceptionInfo(try_catch);
 }
 
 void RunTest(std::string test) {
   base::FilePath path;
   PathService::Get(base::DIR_SOURCE_ROOT, &path);
   path = path.AppendASCII("mojo")
              .AppendASCII("public")
              .AppendASCII("bindings")
              .AppendASCII("js")
              .AppendASCII(test);
   RunTestFromFile(path);
 }
 
 // TODO(abarth): Should we autogenerate these stubs from GYP?
 TEST(Harness, mojo_unittests_js) {
   RunTest("mojo_unittests.js");
 }
 
+TEST(Harness, core_unittests_js) {
+  RunTest("core_unittests.js");
+}
+
 }  // namespace
 }  // namespace js
 }  // namespace mojo