According to someone on JB thrills, someone mentioned that it will open up early June, mainly before June 12th, since that is when Shoreline pier is set to open.
"We are panning to open around June 12th. For people setting calendars, we made sure it is after Tormenta."
You can reply the real comment, since I am quoting it from memory.
EDIT: I have a good idea of whet they could be doing: They could be testing rn, but in the night, when almost everyone in the area is asleep. It is the coldest times in Texas, so it would make sense that they would do it in secret, to make sure everything runs properly.