CTest CDash scripts can use the function ctest_empty_binary_directory to recursively remove a CMake build directory to avoid hidden state between test runs in an overall build-test cycle. However, this function will cause the overall CTest run to return a non-zero error code if CMakeCache.txt isn’t present in the build directory. This is confusing in a CI system particularly. While we do appreciate this safety feature over simply using file(REMOVE_RECURSE), it’s necessary to enclose in if() statements like below to avoid false errors.

if(EXISTS ${CTEST_BINARY_DIRECTORY}/CMakeCache.txt)
  ctest_empty_binary_directory(${CTEST_BINARY_DIRECTORY})
endif()

# ctest_start(), etc.