Yes Basecamp calls them Designer.
In my organization we call the position “Fullstack Designer” in a similar way to a Fullstack Engineer. Because we want this designers to be able to write CSS and HTML and also be able to open Pull Requests on Github.
To assess the skills for that role we give them a pitch of the project so they can see the motivation and some sketches. But we give them the project already solved in terms of data and flow for the developer perspective too.
Also we provide them with our brand theme so they can use it in their designs.
Because that’s usually how that position works in our experience, they try to turn the the fat marker sketches into high fidelity with the tool they use (Figma or XD) to choose colors, spacing, maybe change any affordance or layout.
And then after the developer already connected the data and the flow they style it with their “artistic design” decisions.
We ask them to send us all the designs in their tool of choice but also make a Github PR to a repo in order to see their CSS and HTML implementation.
Hope you find it useful.