trying to find catch2 submodule part 2

CMakeLists.txt

@@ -22,14 +22,16 @@ set(BUILD_PYTHON_PACKAGE OFF CACHE BOOL OFF)
 
 if (COMPILE_TESTS)
     message("-- Trying to find Catch2 to compile the test cases. Turn off via setting 'COMPILE_TESTS=OFF' in your environment before installation. ")
-    set(INTERNAL_findCatch2_DIR ${PROJECT_SOURCE_DIR}/extern/Catch2)
-    set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${INTERNAL_findCatch2_DIR}")
     find_package(Catch2 3)
     if (Catch2_FOUND)         
-        message("-- catch2 library found. Tests will be compiled.")
+        message("-- global installation of catch2 library found. Tests will be compiled.")
     else()
-        message("-- catch2 library not found. Testing disabled.")
-        set(COMPILE_TESTS OFF) 
+        set(INTERNAL_findCatch2_DIR ${PROJECT_SOURCE_DIR}/extern/Catch2)
+        if(NOT EXISTS ${INTERNAL_findCatch2_DIR})
+            message(FATAL_ERROR "The catch2 submodule was not initialized! Please run 'git submodule update --init'. Alternativly you can install catch2 globally on your system." )
+        endif()
+        add_subdirectory(INTERNAL_findCatch2_DIR)
+        message("-- catch2 library found as a submodule. Tests will be compiled.")
     endif()
 else()
     set(Catch2_FOUND OFF)