public void ConvertToExcelTest() { var converter = new NullableConverter(typeof(decimal?)); var typeConverterOptions = new TypeConverterOptions { CultureInfo = CultureInfo.CurrentCulture }; Assert.AreEqual(12.3m, converter.ConvertToExcel(typeConverterOptions, (decimal?)12.3m)); Assert.AreEqual(null, converter.ConvertToExcel(typeConverterOptions, null)); }