TxEngine: add some tests
TxEngine: add some tests

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