Does my employer have the right to search through my lost wallet and take out something they suspected was illegal and test it. And then make me take a drug test before i can work again?

I lost my wallet in the parking lot at my work. I asked the security if anyone had turned in a wallet at all, all day. And they acted strange and told me no. So the next day i showed up to work and asked the same thing. They said no. then they told me i had to do a drug test before i went back to work. I failed the drug test and later they told me they had really found my wallet, and they looked through it and found something they thought were drugs, and they had it tested. Are they allowed to go through my wallet like that and then lie to me and tell me they didnt find it, while theyre really searching it and looking for something illegal??? The whole weekend they let me think my wallet was lost, but really they had the wallet and were setting me up. Doesnt seem right.