Many Leica lens users will say that resolution tests don't really tell
you much about a camera lens'

Your not kidding. When I reported results for peoples Lica lenses did I
get a lot of flack. Some of the old time lenses like those for the Speed or
Crown Graphics were superb in these tests.
This is essentially a contrast test and as such I think its usefull for
astronmy. In the actual tests these targets are spread across the entire field
of view so that problems like coma are readily apparent.