Convert unittesting

[GregJohnsonJr]

To demonstrate that some parameters were not translating properly, I created a unit test to assess the convert function. In particular, the mass_diff_to_variable_mod is not converting properly (Parameters will be added to this PR based on when I find them). Please let me know if we need more information! (This is a failing test)

[StSchulze]

Quick comment:
We originally thought that the translation wasn't working for some parameters, but it turned out to be a false alarm.
However, in the process we also realized that the "was_translated" flag isn't always set to true, even if the value translation actually worked, like in this case here for write_mass_diff_to_variable_mod.