DataOutput: add unit test
DataOutput: add unit test

cocosli/mapdb,jankotek/mapdb,lamfire/mapdb,SleimanJneidi/mapdb,pettermahlen/mapdb,jankotek/MapDB,mebigfatguy/mapdb,jankotek/MapDB,morfeo8marc/mapdb,jankotek/mapdb,ringoluo/mapdb,ffjiao/mapdb,olupas/MapDB,codeaudit/mapdb,olupas/MapDB,sumit784/mapdb,binarytemple/mapdb,mebigfatguy/mapdb,hangum/mapdb