--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/llvm/unittests/ObjectYAML/YAML2ObjTest.cpp	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,81 @@
+//===- YAML2ObjTest.cpp --------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ObjectYAML/yaml2obj.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/Object/ObjectFile.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/YAMLTraits.h"
+#include "llvm/Testing/Support/Error.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+using namespace object;
+using namespace yaml;
+
+TEST(yaml2ObjectFile, ELF) {
+  bool ErrorReported = false;
+  auto ErrHandler = [&](const Twine &Msg) { ErrorReported = true; };
+
+  SmallString<0> Storage;
+  std::unique_ptr<ObjectFile> Obj = yaml2ObjectFile(Storage, R"(
+--- !ELF
+FileHeader:
+  Class:    ELFCLASS64
+  Data:     ELFDATA2LSB
+  Type:     ET_REL
+  Machine:  EM_X86_64)", ErrHandler);
+
+  ASSERT_FALSE(ErrorReported);
+  ASSERT_TRUE(Obj);
+  ASSERT_TRUE(Obj->isELF());
+  ASSERT_TRUE(Obj->isRelocatableObject());
+}
+
+TEST(yaml2ObjectFile, Errors) {
+  std::vector<std::string> Errors;
+  auto ErrHandler = [&](const Twine &Msg) {
+    Errors.push_back("ObjectYAML: " + Msg.str());
+  };
+
+  SmallString<0> Storage;
+  StringRef Yaml = R"(
+--- !ELF
+FileHeader:
+  Class:    ELFCLASS64
+  Data:     ELFDATA2LSB
+  Type:     ET_REL
+  Machine:  EM_X86_64
+Symbols:
+  - Name: foo
+  - Name: foo
+  - Name: foo
+)";
+
+  // 1. Test yaml2ObjectFile().
+
+  std::unique_ptr<ObjectFile> Obj = yaml2ObjectFile(Storage, Yaml, ErrHandler);
+
+  ASSERT_FALSE(Obj);
+  ASSERT_TRUE(Errors.size() == 2);
+  ASSERT_TRUE(Errors[0] == "ObjectYAML: repeated symbol name: 'foo'");
+  ASSERT_TRUE(Errors[1] == Errors[0]);
+
+  // 2. Test convertYAML(). 
+
+  Errors.clear();
+  Storage.clear();
+  raw_svector_ostream OS(Storage);
+
+  yaml::Input YIn(Yaml);
+  bool Res = convertYAML(YIn, OS, ErrHandler);
+  ASSERT_FALSE(Res);
+  ASSERT_TRUE(Errors.size() == 2);
+  ASSERT_TRUE(Errors[0] == "ObjectYAML: repeated symbol name: 'foo'");
+  ASSERT_TRUE(Errors[1] == Errors[0]);
+}