Merge pull request #61 from r-burns/system-gtest

Support using system-installed GTest

CMakeLists.txt

@@ -19,6 +19,7 @@ option(MDSPAN_ENABLE_BENCHMARKS "Enable benchmarks." Off)
 option(MDSPAN_ENABLE_COMP_BENCH "Enable compilation benchmarks." Off)
 option(MDSPAN_ENABLE_CUDA "Enable Cuda tests/benchmarks/examples if tests/benchmarks/examples are enabled." Off)
 option(MDSPAN_ENABLE_OPENMP "Enable OpenMP benchmarks if benchmarks are enabled." On)
+option(MDSPAN_USE_SYSTEM_GTEST "Use system-installed GoogleTest library for tests." Off)
 
 # Option to override which C++ standard to use
 set(MDSPAN_CXX_STANDARD DETECT CACHE STRING "Override the default CXX_STANDARD to compile with.")

tests/CMakeLists.txt

@@ -15,33 +15,38 @@ macro(mdspan_add_test name)
   add_test(${name} ${name})
 endmacro()
 
-# adapted from https://github.com/google/googletest/blob/master/googletest/README.md
-configure_file(${PROJECT_SOURCE_DIR}/cmake/googletest/CMakeLists.txt.in googletest-download/CMakeLists.txt)
-execute_process(COMMAND ${CMAKE_COMMAND} -G "${CMAKE_GENERATOR}" .
-  RESULT_VARIABLE result
-  WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/googletest-download
-)
-if(result)
-  message(FATAL_ERROR "CMake step for googletest failed: ${result}")
-endif()
-execute_process(COMMAND ${CMAKE_COMMAND} --build .
-  RESULT_VARIABLE result
-  WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/googletest-download
-)
-if(result)
-  message(FATAL_ERROR "Build step for googletest failed: ${result}")
-endif()
+if(MDSPAN_USE_SYSTEM_GTEST)
+  find_package(GTest CONFIG REQUIRED)
+  add_library(gtest_main ALIAS GTest::gtest_main)
+else()
+  # adapted from https://github.com/google/googletest/blob/master/googletest/README.md
+  configure_file(${PROJECT_SOURCE_DIR}/cmake/googletest/CMakeLists.txt.in googletest-download/CMakeLists.txt)
+  execute_process(COMMAND ${CMAKE_COMMAND} -G "${CMAKE_GENERATOR}" .
+    RESULT_VARIABLE result
+    WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/googletest-download
+  )
+  if(result)
+    message(FATAL_ERROR "CMake step for googletest failed: ${result}")
+  endif()
+  execute_process(COMMAND ${CMAKE_COMMAND} --build .
+    RESULT_VARIABLE result
+    WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/googletest-download
+  )
+  if(result)
+    message(FATAL_ERROR "Build step for googletest failed: ${result}")
+  endif()
 
-# Prevent overriding the parent project's compiler/linker
-# settings on Windows
-set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
+  # Prevent overriding the parent project's compiler/linker
+  # settings on Windows
+  set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
 
-# Add googletest directly to our build. This defines
-# the gtest and gtest_main targets.
-add_subdirectory(${CMAKE_CURRENT_BINARY_DIR}/googletest-src
-  ${CMAKE_CURRENT_BINARY_DIR}/googletest-build
-  EXCLUDE_FROM_ALL
-)
+  # Add googletest directly to our build. This defines
+  # the gtest and gtest_main targets.
+  add_subdirectory(${CMAKE_CURRENT_BINARY_DIR}/googletest-src
+    ${CMAKE_CURRENT_BINARY_DIR}/googletest-build
+    EXCLUDE_FROM_ALL
+  )
+endif()
 
 mdspan_add_test(test_extents)
 mdspan_add_test(test_mdspan_ctors)