The test was put together by Walmart Labs. The app let employees scan items on their phones but not pay on the devices. Instead the app transferred all scanned items to a self-checkout kiosk.
But Walmart has said it's working on a mobile payment network with other retailers that could rival current solutions like Google Wallet.
Walmart spokesman David Tovar tells Reuters the company is "continually testing new and innovative ways to serve customers and enhance the shopping experience in our stores."
Walmart's US stores spend about $12 millions on cashier wages per second, so an app like this could save the company a lot of money.