As a developer what do I test and what is my focus? As discussed in What is an EUT, earlier EUTS in L1/L2/L3 are “Structural component” , the building block(s) for a feature. As a developer, my primary focus is build these and integrate these to deliver features which combine to form requirements and later flows.

So as a developer my focus is deliver clean “Structural component(s)” and Features. Hence as a developer my EUTs of focus are “Structural component” and “Feature”.