Fix problems while using local packages

update CPM.cmake version too

Set FORCE option for SOURCE_DIR usage

cmake/CPM.cmake

@@ -1,4 +1,4 @@
-set(CPM_DOWNLOAD_VERSION 0.37.0)
+set(CPM_DOWNLOAD_VERSION 0.38.2)
 
 if(CPM_SOURCE_CACHE)
   set(CPM_DOWNLOAD_LOCATION "${CPM_SOURCE_CACHE}/cpm/CPM_${CPM_DOWNLOAD_VERSION}.cmake")
@@ -27,6 +27,7 @@ else()
   if("${check}" STREQUAL "")
     download_cpm()
   endif()
+  unset(check)
 endif()
 
 include(${CPM_DOWNLOAD_LOCATION})

standalone/CMakeLists.txt

@@ -16,7 +16,11 @@ CPMAddPackage(
   OPTIONS "CXXOPTS_BUILD_EXAMPLES NO" "CXXOPTS_BUILD_TESTS NO" "CXXOPTS_ENABLE_INSTALL YES"
 )
 
-CPMAddPackage(NAME Greeter SOURCE_DIR ${CMAKE_CURRENT_LIST_DIR}/..)
+CPMAddPackage(
+  NAME Greeter
+  SOURCE_DIR ${CMAKE_CURRENT_LIST_DIR}/..
+  FORCE ON
+)
 
 # ---- Create standalone executable ----
 

test/CMakeLists.txt

@@ -21,7 +21,11 @@ CPMAddPackage("gh:TheLartians/Format.cmake@1.7.3")
 if(TEST_INSTALLED_VERSION)
   find_package(Greeter REQUIRED)
 else()
-  CPMAddPackage(NAME Greeter SOURCE_DIR ${CMAKE_CURRENT_LIST_DIR}/..)
+  CPMAddPackage(
+    NAME Greeter
+    SOURCE_DIR ${CMAKE_CURRENT_LIST_DIR}/..
+    FORCE ON
+  )
 endif()
 
 # ---- Create binary ----
@@ -46,11 +50,13 @@ endif()
 enable_testing()
 
 # Note: doctest and similar testing frameworks can automatically configure CMake tests. For other
-# testing frameworks add the tests target instead: add_test(NAME ${PROJECT_NAME} COMMAND
-# ${PROJECT_NAME})
-
-include(${doctest_SOURCE_DIR}/scripts/cmake/doctest.cmake)
-doctest_discover_tests(${PROJECT_NAME})
+# testing frameworks add the tests target instead:
+if(NOT doctest_SOURCE_DIR)
+  add_test(NAME ${PROJECT_NAME} COMMAND ${PROJECT_NAME})
+else()
+  include(${doctest_SOURCE_DIR}/scripts/cmake/doctest.cmake)
+  doctest_discover_tests(${PROJECT_NAME})
+endif()
 
 # ---- code coverage ----