--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/unittests/Support/DebugTest.cpp	Fri Oct 27 17:07:41 2017 +0900
@@ -0,0 +1,34 @@
+//===- llvm/unittest/Support/DebugTest.cpp --------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+#include "gtest/gtest.h"
+
+#include <string>
+using namespace llvm;
+
+#ifndef NDEBUG
+TEST(DebugTest, Basic) {
+  std::string s1, s2;
+  raw_string_ostream os1(s1), os2(s2);
+  static const char *DT[] = {"A", "B"};  
+  
+  llvm::DebugFlag = true;
+  setCurrentDebugTypes(DT, 2);
+  DEBUG_WITH_TYPE("A", os1 << "A");
+  DEBUG_WITH_TYPE("B", os1 << "B");
+  EXPECT_EQ("AB", os1.str());
+
+  setCurrentDebugType("A");
+  DEBUG_WITH_TYPE("A", os2 << "A");
+  DEBUG_WITH_TYPE("B", os2 << "B");
+  EXPECT_EQ("A", os2.str());
+}
+#endif