My dd arrived at school and I just left her at the door as normal but she came running back to me in a mild panic as her desk had been moved (all the desks!) and she didn't know where to sit. There was a paper and pencil set out at each end of the tables so I figured SATS.
I think not knowing where to sit made her worry more than the realisation of a test.
Her teacher was busy at her desk, with her back to the door, not welcoming the children in.
YR2 teachers, wouldn't you prepare your class that this sort of thing would be happening?