While Compose is easy to adopt, not creating legacy code right at the start of such a journey requires some extra planning, awareness, and most importantly, testing. We'll have a look at how we can test pure Compose UIs as well as hybrid ones that have Views and composables too. In this talk, we'll learn what the semantics tree is, what is its relation to the composition, how we can manipulate it in composables using the Semantics modifier, how we can implement composables with testability in mind, and how we can test pure Compose and hybrid UIs.