Apart from LF the only allowed white space character is Space (ASCII value 32). Note that this implies that other white space characters (in, for instance, string and character literals) must be written in escaped form.
\n should be preferred over corresponding octal (e.g.
\047) or Unicode (e.g.
\u0027) escaped characters.
Should there be a need to go against the above rules for the sake of testing, the test should generate the required input programatically.