Issue while enabling tests with newer CMake version

[pramodk]

While testing cmake with v3.19.6, I see:

$ cmake --version
cmake version 3.19.6


$ cmake ..  -DNRN_ENABLE_INTERVIEWS=OFF  -DNRN_ENABLE_MPI=OFF  -DNRN_ENABLE_RX3D=OFF -DNRN_ENABLE_CORENEURON=ON -DCMAKE_INSTALL_PREFIX=$HOME/nrn -DNRN_ENABLE_TESTS=ON
.....
-- --------------+--------------------------------------------------------------
--  See documentation : https://github.com/BlueBrain/CoreNeuron/
-- --------------+--------------------------------------------------------------
--
-- Sub-module : missing /Users/kumbhar/Downloads/nrn/external/catch2 : running git submodule update --init
Submodule 'external/catch2' (https://github.com/catchorg/Catch2.git) registered for path 'external/catch2'
Cloning into '/Users/kumbhar/Downloads/nrn/external/catch2'...
Submodule path 'external/catch2': checked out '930f49a641aa6a495d264d7b5e7c007734da0b0c'
-- Found pytest: /opt/homebrew/lib/python3.9/site-packages/pytest (found version "6.2.2")
-- Sub-module : missing test/rxd/testdata : running git submodule update --init
Submodule 'test/rxd/testdata' (https://github.com/neuronsimulator/rxdtestdata) registered for path 'test/rxd/testdata'
Cloning into '/Users/kumbhar/Downloads/nrn/test/rxd/testdata'...
Submodule path 'test/rxd/testdata': checked out 'a60d222a234621d4afd3821a33baa26796f7aad6'
-- Sub-module : missing external/tests/ringtest : running git submodule update --init
Submodule 'external/tests/ringtest' (https://github.com/neuronsimulator/ringtest) registered for path 'external/tests/ringtest'
Cloning into '/Users/kumbhar/Downloads/nrn/external/tests/ringtest'...
Submodule path 'external/tests/ringtest': checked out 'ee24c8e2625df5e90e5e905eea0325d0731ca23b'
CMake Error at test/external/ringtest/CMakeLists.txt:25 (get_filename_component):
  get_filename_component called with incorrect number of arguments

[pramodk]

CMake doc says:

MPIEXEC
Use MPIEXEC_EXECUTABLE instead.

So we expect MPIEXEC to be present but if I look at CMake variables then:

bb-fvff266jq05n:build kumbhar$ grep MPIEXEC CMakeCache.txt
AUTO_TEST_WITH_MPIEXEC:BOOL=ON
MPIEXEC_EXECUTABLE:FILEPATH=/opt/homebrew/bin/mpiexec
MPIEXEC_MAX_NUMPROCS:STRING=8
MPIEXEC_NUMPROC_FLAG:STRING=-n
MPIEXEC_POSTFLAGS:STRING=
MPIEXEC_PREFLAGS:STRING=
//ADVANCED property for variable: MPIEXEC_EXECUTABLE
MPIEXEC_EXECUTABLE-ADVANCED:INTERNAL=1
//ADVANCED property for variable: MPIEXEC_MAX_NUMPROCS
MPIEXEC_MAX_NUMPROCS-ADVANCED:INTERNAL=1
//ADVANCED property for variable: MPIEXEC_NUMPROC_FLAG
MPIEXEC_NUMPROC_FLAG-ADVANCED:INTERNAL=1
//ADVANCED property for variable: MPIEXEC_POSTFLAGS
MPIEXEC_POSTFLAGS-ADVANCED:INTERNAL=1
//ADVANCED property for variable: MPIEXEC_PREFLAGS
MPIEXEC_PREFLAGS-ADVANCED:INTERNAL=1

So seems like they have broken something.