Remove external cmake project for gtest

Now only build tests if a gtest installation already exists on the system. This should expedite time to build for users that do not care about building/running unit tests and also eliminates the need for internet access when building.

CMakeLists.txt

@@ -157,40 +157,15 @@ install(
 ###########
 
 if(LIBCREATE_BUILD_TESTS)
+  find_package(GTest)
+  include_directories(${GTEST_INCLUDE_DIRS})
+endif()
+
+if(LIBCREATE_BUILD_TESTS AND ${GTEST_FOUND})
+  message("GTest installation found. Building tests.")
+
   enable_testing()
 
-  # 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 GTEST_DOWNLOAD_RESULT
-    WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/googletest-download
-  )
-
-  if(GTEST_DOWNLOAD_RESULT)
-    message(FATAL_ERROR "CMake step for googletest failed: ${GTEST_DOWNLOAD_RESULT}")
-  endif()
-
-  # Build googletest
-  execute_process(COMMAND ${CMAKE_COMMAND} --build .
-    RESULT_VARIABLE GTEST_BUILD_RESULT
-    WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/googletest-download
-  )
-
-  if(GTEST_BUILD_RESULT)
-    message(FATAL_ERROR "Build step for googletest failed: ${GTEST_BUILD_RESULT}")
-  endif()
-
-  # Add googletest directly to our build. This defines the gtest and gtest_main targets.
-  add_subdirectory(${CMAKE_BINARY_DIR}/googletest-src
-                   ${CMAKE_BINARY_DIR}/googletest-build)
-
-  # The gtest/gtest_main targets carry header search path
-  # dependencies automatically when using CMake 2.8.11 or
-  # later. Otherwise we have to add them here ourselves.
-  if (CMAKE_VERSION VERSION_LESS 2.8.11)
-    include_directories("${gtest_SOURCE_DIR}/include")
-  endif()
-
   # Add tests
   set(LIBCREATE_TESTS
     test_create
@@ -205,8 +180,8 @@ if(LIBCREATE_BUILD_TESTS)
     add_executable(${LIBCREATE_TEST} tests/${LIBCREATE_TEST}.cpp)
 
     target_link_libraries(${LIBCREATE_TEST}
-      # ${Boost_LIBRARIES}
       ${LIBRARY_NAME}
+      ${GTEST_LIBRARIES}
       gtest_main
     )
 
@@ -215,4 +190,6 @@ if(LIBCREATE_BUILD_TESTS)
       COMMAND ${LIBCREATE_TEST}
     )
   endforeach()
+else()
+  message("No GTest installation found. Skipping tests.")
 endif()

CMakeLists.txt.in

@@ -1,15 +0,0 @@
-cmake_minimum_required(VERSION 2.8.2)
-
-project(googletest-download NONE)
-
-include(ExternalProject)
-ExternalProject_Add(googletest
-  GIT_REPOSITORY    https://github.com/google/googletest.git
-  GIT_TAG           master
-  SOURCE_DIR        "${CMAKE_BINARY_DIR}/googletest-src"
-  BINARY_DIR        "${CMAKE_BINARY_DIR}/googletest-build"
-  CONFIGURE_COMMAND ""
-  BUILD_COMMAND     ""
-  INSTALL_COMMAND   ""
-  TEST_COMMAND      ""
-)

package.xml

@@ -16,8 +16,6 @@
 
   <buildtool_depend>cmake</buildtool_depend>
 
-  <build_depend>git</build_depend>
-
   <depend>boost</depend>
 
   <exec_depend>catkin</exec_depend>