Use GTest imported target in tests/CMakelists.txt

CMakeLists.txt

@@ -102,8 +102,6 @@ if (PISTACHE_BUILD_TESTS)
             add_subdirectory(${googletest_SOURCE_DIR} ${googletest_BINARY_DIR})
         endif()
     endif()
-
-    enable_testing()
     add_subdirectory(tests)
 endif()
 

tests/CMakeLists.txt

@@ -5,8 +5,13 @@ function(pistache_test test_name)
     set(TEST_SOURCE ${test_name}.cc)
 
     add_executable(${TEST_EXECUTABLE} ${TEST_SOURCE})
-    target_include_directories(${TEST_EXECUTABLE} PRIVATE ${GTEST_INCLUDE_DIRS} ${CURL_INCLUDE_DIRS})
-    target_link_libraries(${TEST_EXECUTABLE} gtest gtest_main pistache_static ${CURL_LIBRARIES})
+    target_include_directories(${TEST_EXECUTABLE} PRIVATE ${CURL_INCLUDE_DIRS})
+    # CMake 3.20 and upstream GTest define GTest::gtest, older versions define GTest::GTest
+    if (TARGET GTest::gtest)
+        target_link_libraries(${TEST_EXECUTABLE} GTest::gtest GTest::gtest_main pistache_static ${CURL_LIBRARIES})
+    else ()
+        target_link_libraries(${TEST_EXECUTABLE} GTest::GTest GTest::Main pistache_static ${CURL_LIBRARIES})
+    endif ()
     add_test(${test_name} ${TEST_EXECUTABLE})
 endfunction()