private void when_building_the_default_exception_message()
 {
     _result = ShouldBeNullAssertionException.CreateMessage(ExpectedMessageBuilder.ToDisplayableString(_input));
 }
 public static T?ShouldBeNull <T>(this T?item) where T : struct
 {
     return(ShouldBeNull(item, () => ShouldBeNullAssertionException.CreateMessage(ExpectedMessageBuilder.ToDisplayableString(item))));
 }