ENH: Check that test files provide minimal inputs

[MImmesberger]

Is your feature request related to a problem?

Some test files probably contain unnecessary input columns, we should check that.

At GETTSIM-personas we use this check, probably easy to adapt for GETTSIM tests:

def test_persona_inputs_does_not_contain_unnecessary_inputs(year, persona_class):
    policy_date_str = f"{year}-01-01"
    persona = persona_class(policy_date_str=policy_date_str)
    root_nodes = main(
        main_target=MainTarget.labels.root_nodes,
        policy_date_str=policy_date_str,
        input_data=InputData.tree(persona.input_data_tree),
        tt_targets=TTTargets.tree(persona.tt_targets_tree),
        include_warn_nodes=False,
    )
    input_qnames = dt.flatten_to_qnames(persona.input_data_tree)
    unnecessary_inputs = set(input_qnames) - set(root_nodes) - {"hh_id", "p_id"}
    assert not unnecessary_inputs

Note that sometimes unnecessary inputs may be justified (e.g. keeping hh_id just to make the household structure clear).