Style style = cm.buildStyle();
// print(style);
// round up the basic elements and check its simple
StyleCollector collector = new StyleCollector();
style.accept(collector);
assertSimpleStyle(collector);
// check the symbolizer
RasterSymbolizer rs = (RasterSymbolizer) collector.symbolizers.get(0);
assertEquals(0.3, rs.getOpacity().evaluate(null, Double.class), 0.0);