Test if fnameescape is correct for special chars like !

STARTTEST
:%d
:let fname = 'Xspa ce'
:try | exe "w! " . fnameescape(fname) | put='Space' | endtry 
:let fname = 'Xemark!'
:try | exe "w! " . fnameescape(fname) | put='ExclamationMark' | endtry
:w! test.out
:qa!
ENDTEST