Yes, test-drive plates are not exempted and treated just like normal license plates and subject to the mandatory e-vignette.
Vehicles that exceed 3.5 tonnes of permissible weight use the distance-based toll system (MYTO) instead of the e-vignette.
Related articles:
What vehicles need a Slovak e-vignette?
Where can I buy the Slovak motorway e-vignette?
Does the Slovak e-vignette activate immediately?