Harmonize source, input and executable file names in test folder
Following the majority, I'd suggest
input for the source/input and
_discretization for the target. The problem/appl specific for the source/input may be shortened if it appears already as a subfolder name.
For example, in
test/porousmediumflow/2p/implicit/incompressible, the source/input would be named
input, while a target would be named
test_2p_incompressible_tpfa. I could also live with only
main.cc for the source if there only is one, but wouldn't know something good for the input.
I would omit the
fv since all we do is fv and I would not expect the source/input to become different once we use fe or fd.
For the multidomain models, I'd put an underscore between the coupled models, so
test_stokes1p2c_darcy1p2c_horizontal rather than