Add tests for null sink developed previously in cycamore repository
Add tests for null sink developed previously in cycamore repository

Baaaaam/cyclus,rwcarlsen/cyclus,rwcarlsen/cyclus,rwcarlsen/cyclus,mbmcgarry/cyclus,gidden/cyclus,gidden/cyclus,mbmcgarry/cyclus,hodger/cyclus,mbmcgarry/cyclus,hodger/cyclus,Baaaaam/cyclus,hodger/cyclus,Baaaaam/cyclus,gidden/cyclus,hodger/cyclus,mbmcgarry/cyclus,gidden/cyclus,hodger/cyclus,rwcarlsen/cyclus