GoogleTest 1.14.0 when C++14 compiler available

CHANGES.md

@@ -7,6 +7,7 @@
   shared library otherwise; that is the same pattern followed by opencv.
   The variable should be explicitly set to `ON` if a shared library must
   be created, and `OFF` if a static library must be created.
+- Use GoogleTest 1.14.0 and enable tests only when C++14 compiler available.
 
 ## 0.9.0
 

tests/CMakeLists.txt

@@ -1,3 +1,26 @@
+# googletest
+# ----------
+#
+# The 1.14.x branch requires at least C++14.
+#
+# In particular, 19.34+ (MSVC 2022) is required for Visual Studio:
+# Avoid GoogleTest 1.14.0 error:
+#   [build] C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.35.32215\include\yvals_core.h(811):
+#    error STL1001: Unexpected compiler version, expected MSVC 19.34 or newer.
+#   [build] C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.35.32215\include\yvals_core.h(811):
+#    error C2338: Error in C++ Standard Library usage.
+#   [build] C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.35.32215\include\type_traits(1767):
+#    error C2275: '_Ty1': illegal use of this type as an expression
+if(MSVC)
+  if(MSVC_VERSION LESS 1934)
+    message(STATUS "Tests skipped because MSVC 19.34+ (MSVC 2022) is needed for GoogleTest 1.14+")
+    return()
+  endif()
+elseif(NOT "cxx_std_14" IN_LIST CMAKE_CXX_COMPILE_FEATURES)
+  message(STATUS "Tests skipped because C++14 is needed for GoogleTest 1.14+")
+  return()
+endif()
+
 include(FetchContent)
 FetchContent_Declare(googletest
   GIT_REPOSITORY https://github.com/google/googletest.git
@@ -5,8 +28,8 @@ FetchContent_Declare(googletest
 )
 FetchContent_MakeAvailable(googletest)
 
-include(GoogleTest)
 add_executable(c-capnproto-testcases addressbook.capnp.c capn-stream-test.cpp capn-test.cpp example-test.cpp)
 target_link_libraries(c-capnproto-testcases PRIVATE CapnC_Runtime GTest::gtest)
 
+include(GoogleTest)
 gtest_add_tests(TARGET c-capnproto-testcases)