Set C++17 explicitly in tests for OSX compilation

tests/CMakeLists.txt

@@ -17,6 +17,14 @@ foreach(FILENAME ${TESTS})
         set_target_properties(${TEST_PROJ} PROPERTIES LINK_FLAGS "/SUBSYSTEM:CONSOLE")
     endif()
 
+    if(OSX)
+        set_property(TARGET ${TEST_PROJ} PROPERTY CXX_STANDARD 1z)
+    elseif(UNIX)
+        set_property(TARGET ${TEST_PROJ} PROPERTY CXX_STANDARD 17)
+    elseif(MSVC)
+        set_property(TARGET ${TEST_PROJ} PROPERTY CXX_STANDARD 17)
+    endif()
+
     set_property(TARGET ${TEST_PROJ} PROPERTY FOLDER "com3001/tests") 
     add_test(NAME ${TEST_PROJ} COMMAND ${TEST_PROJ})
 
@@ -28,4 +36,4 @@ foreach(FILENAME ${TESTS})
         COMMAND ${CMAKE_COMMAND}
         -E copy_if_different ${file_i} $<TARGET_FILE_DIR:${TEST_PROJ}>)
     endforeach(file_i)
-endforeach(FILENAME)
+endforeach(FILENAME)
\ No newline at end of file