// Create a file whose name contains unpaired surrogates.
	// Use syscall.CreateFile instead of os.Create to simulate a file that is created by
	// a non-Go program so the file name hasn't gone through syscall.UTF16FromString.
	dirw := utf16.Encode([]rune(dir))
	pathw := append(dirw, namew...)
	fd, err := syscall.CreateFile(&pathw[0], syscall.GENERIC_ALL, 0, nil, syscall.CREATE_NEW, 0, 0)
	if err != nil {
		t.Fatal(err)
	}