Couple of thought provoked by this reponse - my three things when hiring:

* curiosity

* ability to use a logical approach to problem solving

* pragmatism - sometimes in your coding world of binary you have to realize that the domain you are working in isn't

As far as data design is concerned - recall that PROGRAMS = DATA + ALGORITHMS. Really doesn't matter whether it is front or backend, an attention to the data structures being used will make the solution that much more understandable and efficient.

...and we shouldn't have to choose between good coders and good test writers - good coders are good test writers.