Fill in the blank below.

Consider a web$-$based e$-$commerce application that allows users to browse products, add items to the shopping cart, and proceed to checkout. A $\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$ test for this application is a quick and preliminary test performed to verify that the basic functionalities of an application or system are working correctly after a new build or deployment. It helps identify critical issues early on and ensures that further testing can proceed.

$*$Please write your answer in lowercase and ensure spelling is correct.