+static
+void
+test_upper()
+{
+// boost::cnv::strtol cnv;
+// char const* c_lcase = "abcde";
+// char const* c_ucase = "ABCDE";
+// wchar_t const* w_lcase = L"abcde";
+// wchar_t const* w_ucase = L"ABCDE";
+//
+// BOOST_TEST(c_lcase == convert< string>(c_lcase, cnv(arg::uppercase = false)).value_or(""));
+// BOOST_TEST(c_ucase == convert< string>(c_lcase, cnv(arg::uppercase = true)).value_or(""));
+// BOOST_TEST(w_ucase == convert<wstring>(w_lcase, cnv(arg::uppercase = false)).value_or(""));
+// BOOST_TEST(w_ucase == convert<wstring>(w_lcase, cnv(arg::uppercase = true)).value_or(""));
+}
+