You can buy a Test license for the products you have running in Production (Server, Publisher, Connectors, ...) at a reduced price. And you won't need to buy any CALs for the Test environment. It will inherit the licenses from the Production server but won't allow license leasing.
You can contact your ERP vendor (which is probably your designated Qlik Partner and is responsible for managing your licenses). You could also contact another Qlik Account manager or Reseller, but that may involve an initial license transfer.