Believe this is testing of newly installed WiFi. Of course I can't confirm that, but WiFi has been added to several A319s at SFO
and a test hop is usually done before release.
Flyer Talk thread says that A319 N802UA had WiFi operational today on his flight. Rumor was that the WiFi was awaiting some type of government approval. If approved, several A319s should have WiFi turned on - right now the Amenities portion of N802UA does not show WiFi under inflight entertainment.
747-400 N104UA was rumored to have WiFi installation at SFO
, but probably not turned on - would have to be international WiFi.