The winter event has not been activated in BPV Test, since here the focus is on testing the new farm village system.
The additional rewards, boni and effects of the winter event could distort the results, and the developers would not be able to tell apart whether the new features are causing potential changes in the players´ behaviour, their development and the balancing of the world as a whole in its early stages, or whether such potential changes are the result of the rewards and effects of the Winter Event.
In my opinion it is perfectly reasonable to test the new features without such side effects caused by events.