[fix] move dep from gtest to test where it's actually used

Author: pariaspe

tests/CMakeLists.txt

@@ -2,12 +2,14 @@
 file(GLOB TEST_SOURCE "*_test.cpp")
 
 if(TEST_SOURCE)
+  find_package(ament_index_cpp REQUIRED)
+
   foreach(TEST_FILE ${TEST_SOURCE})
     get_filename_component(TEST_NAME ${TEST_FILE} NAME_WE)
 
     add_executable(${PROJECT_NAME}_${TEST_NAME} ${TEST_FILE})
     ament_target_dependencies(${PROJECT_NAME}_${TEST_NAME} ${PROJECT_DEPENDENCIES})
-    target_link_libraries(${PROJECT_NAME}_${TEST_NAME} ${PROJECT_NAME})
+    target_link_libraries(${PROJECT_NAME}_${TEST_NAME} ament_index_cpp::ament_index_cpp ${PROJECT_NAME})
   endforeach()
 endif()
 
@@ -16,13 +18,12 @@ file(GLOB GTEST_SOURCE "*_gtest.cpp")
 
 if(GTEST_SOURCE)
   find_package(ament_cmake_gtest REQUIRED)
-  find_package(ament_index_cpp REQUIRED)
 
   foreach(TEST_SOURCE ${GTEST_SOURCE})
     get_filename_component(TEST_NAME ${TEST_SOURCE} NAME_WE)
 
     ament_add_gtest(${PROJECT_NAME}_${TEST_NAME} ${TEST_SOURCE})
     ament_target_dependencies(${PROJECT_NAME}_${TEST_NAME} ${PROJECT_DEPENDENCIES})
-    target_link_libraries(${PROJECT_NAME}_${TEST_NAME} ament_index_cpp::ament_index_cpp gtest_main ${PROJECT_NAME})
+    target_link_libraries(${PROJECT_NAME}_${TEST_NAME} gtest_main ${PROJECT_NAME})
   endforeach()
 endif()