I had a whopping 0.105 steem, it probably got all ate up by fees, but thought I would give it a test anyways. I will try a real test on Wednesday afternoon.
Well that was fast:
Received from swap.app0.083 HIVE
2 minutes ago
0.105 STEEM -> 0.083 HIVE (1 STEEM = 0.79 HIVE)
And fees did not eat it all up. :-}