bug#42883: Selecting a subset of tests in recursive make causes unnecessary failures

[Karl Berry]

    at a minimum this behavior should be documented
    with the test subsets documentation and this work around mentioned.

Yes, I agree. Contemplating.

    Ideally, the subset tests feature design should be updated to play nice
    with makefile recursion.

I think I agree again, but ... not sure ...

    Another issue is that if there is a test X in the root makefile and a
    test X in SUBDIR

Isn't that fundamentally not supported, or supportable? I admit I don't
actually know if there's any history about it, but using the same name
for two tests in different places just seems like a basic source of
confusion. As far as I know, the TESTS mechanism just isn't set up to
be able to specify arbitrary test names in arbitrary directories.

Admittedly if it is not supported, it could at least be detected and
complained about. On the other hand, I suppose it works when not
explicitly specifying tests to run, which is 99% of the time. So, once
again ... I don't know. Nothing is ever simple :).

Jim, Paul, anyone? --thanks, karl.