In our school we also do not tell our Year 2 or 6 children about Sats - because we don't do them in our school; we have key stage tests.
We do not tell the children when the tests are going to be. Of course we let them practise old question papers beforehand, - but it is not a big deal so when they do the "real" tests they don't realise it: "Oh it's another one of those!"
Parents are told that the tests are not important to their children - the results won't make any difference to their lives. If parents become anxious we tell them that their children aren't being tested, it is the school and teachers: when we received a letter from David Milliband informing us we have been awarded a School Achievement Award, he congratulated the staff, not the children.
Singleton CE primary school Chichester West Sussex