Set CXX_STANDARD in a way that allows for a higher standard having be…

…en set.

tests/CMakeLists.txt

@@ -4,7 +4,12 @@ if(MESSAGE_LOG_LEVEL IN_LIST LOG_LEVELS_FOR_INDENTATION)
 endif()
 
 
-set(CMAKE_CXX_STANDARD 14) # probably not needed if GTest is found
+# May not be needed.  Linking a target with gtest_main or gmock seems
+# to force C++14 to be used regardless.
+if(CMAKE_CXX_STANDARD LESS 14)
+  message(VERBOSE "GoogleTest requires at least C++14")
+  set(CMAKE_CXX_STANDARD 14)
+endif()
 
 # Get GoogleTest if we don't have it:
 include(FetchContent)
@@ -18,11 +23,6 @@ FetchContent_Declare(
 set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
 FetchContent_MakeAvailable(googletest)
 
-add_custom_target(blah ALL
-                       COMMAND ls -l test_all > test_all_info
-                       )
-#add_dependencies(blah test_all)
-
 
 add_executable(test_all
                test_regression.cpp