Fix the test for source to sink scenario.
Fix the test for source to sink scenario.

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