coll.insert(new MockObject("baz", 1));
coll.insert(new MockObject("qux", 1));
AggregationBuilder<MockObjectAggregationResult> builder = new AggregationBuilder<MockObjectAggregationResult>();
builder.group(new GroupAggregation("string"))
.limit(new LimitAggregation(2));
AggregationResult<MockObjectAggregationResult> aggregationResult = coll.aggregate(builder.build(MockObjectAggregationResult.class));
Assert.assertEquals(2, aggregationResult.results().size());