[CMake] add_custom_command on test input files

[Olaf Peter]

Hello,

for my project I have a sub dir with test case which feeds the tests 
'*.input' and allows to check to output '*.expected'. For documentation 
purpose, I have a python script which generates a TestMatrix.rst file. 
Using CMake I have:

dir structure:

$root/{src,include,utils,test}

test/CMakeLists.txt

project(test LANGUAGES CXX)
...

set(TEST_MATRIX_GENERATOR 
${CMAKE_CURRENT_SOURCE_DIR}/../utils/gen_test_matrix.py)
set(TEST_MATRIX_GENERATOR_TARGET 
${CMAKE_CURRENT_SOURCE_DIR}/test_matrix.rst)
file(GLOB_RECURSE TEST_CASE_FILES
     LIST_DIRECTORIES true
     "${CMAKE_CURRENT_SOURCE_DIR}/test_case/" "*.expected"
)
add_custom_command(
     TARGET  ${PROJECT_NAME} POST_BUILD
     COMMAND ${TEST_MATRIX_GENERATOR} ${CMAKE_CURRENT_SOURCE_DIR} > 
${TEST_MATRIX_GENERATOR_TARGET}
     DEPENDS ${TEST_MATRIX_GENERATOR} ${TEST_CASE_FILES}
     BYPRODUCT ${TEST_MATRIX_GENERATOR_TARGET}
     COMMENT "Generate TestCase Matrix (RST)"
)

set_source_files_properties(
     ${TEST_MATRIX_GENERATOR_TARGET}
     PROPERTIES GENERATED TRUE
)

but I assume, this isn't clever since it doesn't depend on the test_case 
dirs/files as I've seen so far. Changes in these file doesn't trigger 
the generation process, removing the ${TEST_MATRIX_GENERATOR_TARGET} 
doesn't recreate it. How to get it working/generating on each changes 
(additions) of the files/dirs in test_case?


Thanks,

Olaf