Found the solution with no coding necessary: prove takes an --exec option:

$ prove -r --ext .tap -e /bin/cat
./O.linux-x86_64/blockingSockTest.tap ......... ok
./O.linux-x86_64/epicsAlgorithmTest.tap ....... ok
./O.linux-x86_64/epicsCalcTest.tap ............ ok

...

./O.linux-x86_64/ringBytesTest.tap ............ ok
./O.linux-x86_64/ringPointerTest.tap .......... ok
./O.linux-x86_64/taskwdTest.tap ............... ok
All tests successful.
Files=27, Tests=2083,  0 wallclock secs ( 0.41 usr  0.06 sys +  0.00 cusr  0.08 csys =  0.55 CPU)
Result: PASS