@Test
public void testSum() throws Exception {

    SimpleFeatureSource source = bugs.getFeatureSource("bugsites");
    Set<AggregationFunction> functions = EnumSet.of(AggregationFunction.Sum);
    
    Results result = AggregateProcess.process( source.getFeatures(), "cat",  functions, true, null );
    assertTrue( result.sum > 0 );
}