### Question:
RandomAggregateFunction extends DefaultAggregateFunction<Object> { @Override public AggregateBuilder<?> createAggregateBuilder() { return new RandomAggregateBuilder(); }  @Override AggregateBuilder<?> createAggregateBuilder(); @Override String getFunctionName();  }### Answer:
@Test public void testBuildAggregate() throws Exception { final AggregateBuilder<?> aggregateBuilder = FUNCTION.createAggregateBuilder(); aggregateBuilder.add("foo"); aggregateBuilder.add("bar"); aggregateBuilder.add("baz"); final Object aggregate = aggregateBuilder.getAggregate(); assertTrue(Arrays.asList("foo", "bar", "baz").contains(aggregate)); }