A usability test (or user test) is a moderated test to gain valuable insights any time in the process. A usability test is a good starting point for a redesign or competitor analysis early on. During a project the test can be used to explore (different) concepts or a beta version of the product. At the end of the process we use it to figure out how people receive the product. But also to see how we can improve the design. The end goal of a usability test is always to gather user feedback to improve the design.
Yesterday we did some usability tests as a part of our Design Sprint
To usability test
Tomorrow we're usability testing our new prototype with some end-users