Added basic framework for creating cxx20 test cases

tests/CMakeLists.txt

@@ -3,6 +3,8 @@ file(GLOB_RECURSE TEST_CASE_SOURCES t*/*.cc t*/*.c t*/src/*.c)
 file(GLOB_RECURSE TEST_CASE_CONFIGS t*/.clang-uml)
 file(GLOB_RECURSE TEST_CONFIG_YMLS test_config_data/*.yml)
 
+set(TEST_CASES_REQUIRING_CXX20 t00056)
+
 set(CLANG_UML_TEST_LIBRARIES
         clang-umllib
         ${YAML_CPP_LIBRARIES}
@@ -13,6 +15,23 @@ if(MSVC)
     list(APPEND CLANG_UML_TEST_LIBRARIES "Version.lib")
 endif(MSVC)
 
+list(FIND CMAKE_CXX_COMPILE_FEATURES cxx_std_20 SUPPORTS_CXX_STD_20)
+
+if(SUPPORTS_CXX_STD_20 EQUAL -1
+        OR ${LLVM_PACKAGE_VERSION} VERSION_LESS "15.0")
+    set(ENABLE_CXX_STD_20_TEST_CASES 0)
+    foreach(CXX20_TC ${TEST_CASES_REQUIRING_CXX20})
+        list(FILTER TEST_CASE_SOURCES
+                EXCLUDE
+                REGEX ".*${CXX20_TC}.*")
+        list(FILTER TEST_CASE_CONFIGS
+                EXCLUDE
+                REGEX ".*${CXX20_TC}.*")
+    endforeach()
+else()
+    set(ENABLE_CXX_STD_20_TEST_CASES 1)
+endif()
+
 set(TEST_CASES
         test_util
         test_model
@@ -27,11 +46,14 @@ foreach(TEST_NAME ${TEST_CASES})
             ${TEST_NAME}.cc
             $<$<STREQUAL:${TEST_NAME},test_cases>:${TEST_CASE_SOURCES}>
             catch.h)
-    target_compile_features(${TEST_NAME} PRIVATE cxx_std_17)
+    target_compile_features(${TEST_NAME} PRIVATE
+            $<IF:${ENABLE_CXX_STD_20_TEST_CASES},cxx_std_20,cxx_std_17>)
+    target_compile_definitions(${TEST_NAME} PRIVATE
+            $<$<EQUAL:${ENABLE_CXX_STD_20_TEST_CASES},1>:ENABLE_CXX_STD_20_TEST_CASES>)
     target_compile_options(${TEST_NAME} PRIVATE
             $<$<OR:$<CXX_COMPILER_ID:Clang>,$<CXX_COMPILER_ID:GNU>>:
             -Wno-unused-parameter -Wno-unused-private-field -Wno-unused-variable
-            -Wno-attributes -Wno-nonnull>
+            -Wno-attributes -Wno-nonnull -Wno-deprecated-enum-enum-conversion>
             $<$<CXX_COMPILER_ID:MSVC>:/MP /W1 /bigobj /wd4624>)
     target_link_libraries(${TEST_NAME} PRIVATE ${CLANG_UML_TEST_LIBRARIES})
 endforeach()