http://blog.csdn.net/kiwi_coder/article/details/37873093
内存mongo
https://github.com/flapdoodle-oss/de.flapdoodle.embed.mongo
https://github.com/fakemongo/fongo
https://github.com/thiloplanz/jmockmongo - mongodb mocking
https://github.com/lordofthejars/nosql-unit - extended nosql unit testing
https://github.com/jirutka/embedmongo-spring - Spring Factory Bean for EmbedMongo