Add aggregation test.
Add aggregation test.

buaasun/grappa,alexfrolov/grappa,uwsampa/grappa,uwsampa/grappa,uwsampa/grappa,buaasun/grappa,alexfrolov/grappa,alexfrolov/grappa,uwsampa/grappa,alexfrolov/grappa,uwsampa/grappa,buaasun/grappa,buaasun/grappa,alexfrolov/grappa,alexfrolov/grappa,uwsampa/grappa,uwsampa/grappa,alexfrolov/grappa,buaasun/grappa,buaasun/grappa,buaasun/grappa