if(NOT trout_GOOGLETEST_ROOT_DIR)
  set(trout_GOOGLETEST_ROOT_DIR ${CMAKE_CURRENT_SOURCE_DIR}/third_party/googletest)
endif()

if(EXISTS "${trout_GOOGLETEST_ROOT_DIR}/CMakeLists.txt")
  if(TARGET ${_trout_GOOGLETEST_LIBRARY_NAME})
    set(trout_GOOGLETEST_LIBRARIES ${_trout_GOOGLETEST_LIBRARY_NAME})
  else()
    set(trout_GOOGLETEST_LIBRARIES "gtest")
  endif()
  if (NOT TARGET ${trout_GOOGLETEST_LIBRARIES})
    add_subdirectory(${trout_GOOGLETEST_ROOT_DIR} third_party/googletest)
  endif()
else()
  message(FATAL_ERROR "${trout_GOOGLETEST_ROOT_DIR}/CMakeLists.txt not found")
endif()