Test parsing of CSS nth-child tokens.

TEST DID NOT COMPLETE

Rules from the stylesheet:

Expected result:

#a:nth-child(1n+0) { color: green; }
#b:nth-child(n+0) { color: green; }
#c:nth-child(n) { color: green; }
#d:nth-child(-n+0) { color: green; }
#e:nth-child(-n) { color: green; }
#f:nth-child(1N+0) { color: green; }
#g:nth-child(N+0) { color: green; }
#h:nth-child(N) { color: green; }
#i:nth-child(-N+0) { color: green; }
#j:nth-child(-N) { color: green; }
#l:nth-child(-1N
  -
  123) { color: green; }
#m:nth-child(N- 123) { color: green; }
#o:nth-child(23n

 +

123) { color: green; }
#t:nth-child(+n+3) { color: green; }
#u:nth-child(+n + 7) { color: green; }