Test rubric type (test cases) only work for numeric cells -- should work for others too!

[erdogmush]

@erdogmush commented on Fri Jun 11 2021

This is hard, and I guess will be possible only if we can have the formulas evaluated within excel rather than converting them to python and evaluating in python, or if we use a python formula parsing and evaluation library like formulas: https://formulas.readthedocs.io/en/stable/