    @Test
    public void testAttachment() throws Exception {

        String css = 
            "  #states::glow {"+
            "    polygon-fill: #888888;"+
            "    polygon-opacity: 0.25;"+
            "    comp-op: dst;"+
            "  }";

        Style result = Carto.parse(css);
        
        Rule r = result.getRules().get(0);

        assertEquals(new RGB("#888888"), r.eval("polygon-fill", RGB.class));
        assertEquals(0.25, r.eval("polygon-opacity", Double.class), 0.1);
        assertEquals("dst", r.eval("comp-op", String.class));

        assertEquals(1, r.getSelectors().size());
        
        Selector s = r.getSelectors().get(0);
        assertEquals("states", s.getId());
        assertEquals("glow", s.getAttachment());
    }