cmake_minimum_required(VERSION 3.5) project(TestMultiplePackages C) find_package (Python2 REQUIRED COMPONENTS Interpreter Development) find_package (Python3 REQUIRED COMPONENTS Interpreter Development) # Must find Python 3 find_package (Python REQUIRED) if (NOT Python3_EXECUTABLE STREQUAL Python_EXECUTABLE) message (FATAL_ERROR "Python interpreters do not match:\n" " Python_EXECUTABLE='${Python_EXECUTABLE}'\n" " Python3_EXECUTABLE='${Python3_EXECUTABLE}'\n" ) endif() Python2_add_library (spam2 MODULE ../spam.c) target_compile_definitions (spam2 PRIVATE PYTHON2) Python3_add_library (spam3 MODULE ../spam.c) target_compile_definitions (spam3 PRIVATE PYTHON3) add_test (NAME python2_spam2 COMMAND "${CMAKE_COMMAND}" -E env "PYTHONPATH=$" "${Python2_EXECUTABLE}" -c "import spam2; spam2.system(\"cd\")") add_test (NAME python3_spam3 COMMAND "${CMAKE_COMMAND}" -E env "PYTHONPATH=$" "${Python3_EXECUTABLE}" -c "import spam3; spam3.system(\"cd\")")