Allow using local GTest (#328)

* Use system version of GTest if available

* Make system GTest optional and add version

configure.sh

@@ -23,6 +23,7 @@ Configures the CMAKE build environment.
 --static-lib            build a static library (default: shared)
 --static                build a static executable (default: dynamic); implies --static-lib
 --with-profiling        build with gperftools for profiling (default: off)
+--no-system-gtest       do not use system GTest sources; forces download (default: off)
 EOF
   exit 0
 }
@@ -44,6 +45,7 @@ python=default
 lib_type=SHARED
 static_exec=NO
 with_profiling=default
+system_gtest=default
 
 buildtype=Release
 
@@ -90,6 +92,7 @@ do
             lib_type=STATIC;
             ;;
         --with-profiling) with_profiling=ON;;
+        --no-system-gtest) system_gtest=no;;
         *) die "unexpected argument: $1";;
     esac
     shift
@@ -121,6 +124,9 @@ cmake_opts="-DCMAKE_BUILD_TYPE=$buildtype -DPONO_LIB_TYPE=${lib_type} -DPONO_STA
 [ $with_profiling != default ] \
     && cmake_opts="$cmake_opts -DWITH_PROFILING=$with_profiling"
 
+[ $system_gtest != default ] \
+    && cmake_opts="$cmake_opts -DSYSTEM_GTEST=$system_gtest"
+
 root_dir=$(pwd)
 
 [ -e "$build_dir" ] && rm -r "$build_dir"

tests/CMakeLists.txt

@@ -1,27 +1,37 @@
 # Set Up Google Tests
 
 # build testing infrastructure
-# Download and unpack googletest at configure time
-configure_file(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()
+option (SYSTEM_GTEST "Should we try to use the system GTest" ON)
 
-# 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)
+if (SYSTEM_GTEST)
+  # try finding a system installation of googletest
+  find_package(GTest 1.14 CONFIG)
+else()
+  set(GTest_FOUND FALSE)
+endif()
 
+if(NOT GTest_FOUND)
+  # Download and unpack googletest at configure time
+  configure_file(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: ${result}")
+  endif()
+    # Add googletest directly to our build. This defines
+    # the gtest and gtest_main targets.
+  add_subdirectory(${CMAKE_CURRENT_BINARY_DIR}/googletest-src
+                   ${CMAKE_CURRENT_BINARY_DIR}/googletest-build
+                   EXCLUDE_FROM_ALL)
+else()
+endif()
 if (WITH_MSAT)
   add_definitions(-DWITH_MSAT)
 endif()
@@ -36,7 +46,7 @@ target_link_libraries(pono-test-lib pono-lib)
 
 macro(pono_add_test name)
   add_executable(${name} "${CMAKE_CURRENT_SOURCE_DIR}/${name}.cpp")
-  target_link_libraries(${name} gtest_main)
+  target_link_libraries(${name} gtest gtest_main)
   target_link_libraries(${name} pono-test-lib) # also includes pono-lib because it's linked
   add_test(NAME ${name} COMMAND ${name})
 endmacro()