With the introduction of taking EMV transactions on the devices themselves, there will NOT be any Test Mode available on our Clover Mobile and Clover Mini devices.
If you would like to run a test transaction the devices, please run a small (i.e. $1.00) transaction within Sale app and refund the amount right afterwards.
Reference Site: https://help.clover.com/faq/how-do-i-enable-test-mode-on-my-clover-mini-or-clover-mobile/