Pump: add test cases for empty source iterators. See #452
Pump: add test cases for empty source iterators. See #452

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