Embodiments herein relate to a test shell for assessing fit in an ear of a user of an ear-wearable device, such as a hearing aid. The test shell includes a body having an aperture end and an ear canal end, the aperture end defines a first aperture, and the body defines a shell cavity extending away from the first aperture in a direction of the ear canal end. The body includes a transparent or translucent material and is sized to fit within an ear of the user of an ear-wearable device. Other embodiments are also included herein.