I checked them again today and there are little brown buds. My husband thinks they're dead, but I'm not sure. Is there any easy way to tell? Will the scratch test work?

I'm a few zones warmer then you and mine are just starting to break dormancy. The vines do look dead but you can see the leaf buds swelling. The living vines are somewhat pliable whereas the dead portions are very brittle. I'd just keep an eye on it and see if the leaf buds continue to swell.
Karyn

This thread is over 10 years old!! You really should start a new one.

Seed grown wisteria can take many years to flower....some sources state as many as 15-20 years. So if your vine is from seed (most commercially sold vines are grafted), that would explain the lack of blooms.

And depending on where you are located, wisteria is only just beginning to emerge from dormancy. And if you have been experiencing the weird spring weather fluctuations much of the eastern half of the country has undergone, full emergence from dormancy may be delayed.

Also, where are you? Some of the Asian wisterias can have their buds damaged by late cold snaps even where the vines are hardy.