At some point very soon you are going to have to talk to her. She owes you the whole truth no matter how obvious it may be now. There is a slim chance that the test wasn't for her, but history does suggest otherwise. You just need to tell her that you found the receipt and you don't feel you can continue without her being completely honest about everything so you can make some informed decisions for yourself.
GH, you need to confirm this and not sit it on it too long. It'll eat you alive. Don't give it the power. There is also that nasty issue about STD's. That's real. You know it.
If she is not willing not admit the truth, or give you proof the test wasn't for her, you should probably question whether she is still the woman you think she is...
But by all means, give her one more chance to tell the truth once you have calmed down.
