cet-is » cetbuildtools

I have a snippet of CMakeLists.txt like:

cet_test(Track_test
  HANDBUILT
  DATAFILES test_trackproxy.fcl
  TEST_EXEC lar --rethrow-all -c ./test_trackproxy.fcl
  USE_BOOST_UNIT
  )

and I receive the error:

CMake Error at /products/cetbuildtools/v5_09_01/Modules/CetTest.cmake:311 (message):
  cet_test: DATAFILES option is now mandatory: non-option arguments are no
  longer permitted.
Call Stack (most recent call first):
  lardata/test/RecoBaseProxy/CMakeLists.txt:6 (cet_test)

This kind of errors happened to me a number of types, where I mistype a keyword (in this case, I should have split the command line between TEST_EXEC and a TEST_ARGS) and cet_test pushes upon me its interpretation of the error rather than detailing what triggered it.
The simplest solution is to hint which was the error token. In my case, TEST_EXEC is actually a valid keyword, so I believe the error token was --rethrow-all. If the message had said:

CMake Error at /products/cetbuildtools/v5_09_01/Modules/CetTest.cmake:311 (message):
  cet_test: non-option argument found: '--rethrow-all'. Non-option arguments are no longer permitted. Also note that DATAFILES option is now mandatory.
Call Stack (most recent call first):
  lardata/test/RecoBaseProxy/CMakeLists.txt:6 (cet_test)

instead of assuming that my mistake of today is from an ancient cet_test breaking change, I would at least been put on the right track.
A more sophisticate logic to detect that I tried to append more arguments to a keyword (TEST_EXEC) than allowed would be ideal, but maybe not worth the effort.