Add a few tests.
Add a few tests.

svn path=/trunk/libcss/; revision=12446

servo/libcss,servo/libcss,zhuyadong/libcss,prepare/netsurf_libcss,prepare/netsurf_libcss,zhuyadong/libcss,prepare/netsurf_libcss,zhuyadong/libcss,servo/libcss