added FIND_GTEST_PACKAGE to force using system-wide gtest version (#106)

CMakeLists.txt

@@ -162,18 +162,25 @@ if(BUILD_TESTING)
     set(THREADS_PREFER_PTHREAD_FLAG ON)
     find_package(Threads REQUIRED)
 
+    option(FIND_GTEST_PACKAGE "Enable finding gtest package." OFF)
+
+    if(FIND_GTEST_PACKAGE)
+        find_package(GTest REQUIRED)
+    else()
+        # gtest, gtest_main, gmock and gmock_main targets are available from now on
+        set(GOOGLETEST_DEPS_DIR ${entt_SOURCE_DIR}/deps/googletest)
+        configure_file(${entt_SOURCE_DIR}/cmake/in/googletest.in ${GOOGLETEST_DEPS_DIR}/CMakeLists.txt)
+        execute_process(COMMAND ${CMAKE_COMMAND} -G "${CMAKE_GENERATOR}" . WORKING_DIRECTORY ${GOOGLETEST_DEPS_DIR})
+        execute_process(COMMAND ${CMAKE_COMMAND} --build . WORKING_DIRECTORY ${GOOGLETEST_DEPS_DIR})
+        set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
+        add_subdirectory(${GOOGLETEST_DEPS_DIR}/src ${GOOGLETEST_DEPS_DIR}/build)
+        add_library(GTest::Main ALIAS gtest_main)
+    endif()
+
     option(BUILD_BENCHMARK "Build benchmark." OFF)
     option(BUILD_MOD "Build mod example." OFF)
     option(BUILD_SNAPSHOT "Build snapshot example." OFF)
 
-    # gtest, gtest_main, gmock and gmock_main targets are available from now on
-    set(GOOGLETEST_DEPS_DIR ${entt_SOURCE_DIR}/deps/googletest)
-    configure_file(${entt_SOURCE_DIR}/cmake/in/googletest.in ${GOOGLETEST_DEPS_DIR}/CMakeLists.txt)
-    execute_process(COMMAND ${CMAKE_COMMAND} -G "${CMAKE_GENERATOR}" . WORKING_DIRECTORY ${GOOGLETEST_DEPS_DIR})
-    execute_process(COMMAND ${CMAKE_COMMAND} --build . WORKING_DIRECTORY ${GOOGLETEST_DEPS_DIR})
-    set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
-    add_subdirectory(${GOOGLETEST_DEPS_DIR}/src ${GOOGLETEST_DEPS_DIR}/build)
-
     enable_testing()
     add_subdirectory(test)
 endif()

test/CMakeLists.txt

@@ -25,7 +25,7 @@ target_compile_features(odr
 
 macro(ADD_ENTT_TEST TEST_NAME TEST_SOURCE)
     add_executable(${TEST_NAME} $<TARGET_OBJECTS:odr> ${TEST_SOURCE})
-    target_link_libraries(${TEST_NAME} PRIVATE EnTT gtest_main Threads::Threads)
+    target_link_libraries(${TEST_NAME} PRIVATE EnTT GTest::Main Threads::Threads)
     set_target_properties(${TEST_NAME} PROPERTIES CXX_EXTENSIONS OFF)
     target_compile_options(${TEST_NAME} PRIVATE $<$<NOT:$<CXX_COMPILER_ID:MSVC>>:-pedantic -Wall>)
     add_test(NAME ${TEST_NAME} COMMAND ${TEST_NAME})