N-basic - basic handling of character number escapes basic usage: x\N'65'x

too large: x\N'259'x

much too large: x\N'2259'x

XXX mandoc ignores non-printable characters, while groff does not
too small: x\N'1'x
.br
null: x\N'0'x
.br
non-numerical content: x\N'XX'x

mixed content: x\N'65XX'x

empty: x\N''x

no quoting: x\N665x

non-matching quoting characters: x\NX65Yx

end of test document