sysbench:
https://mariadb.com/kb/en/mariadb/development/quality/benchmarks-and-long-running-tests/benchmarks/sysbench-benchmark-setup/#custom-added-tests
Could help for integration tests.
spider:
https://mariadb.com/kb/en/mariadb/documentation/storage-engines/spider/spider-storage-engine-overview/
a storage
engine with built-in sharding features.