diff --git a/CMakeLists.txt b/CMakeLists.txt
index b79bf6028..6a86e3f7a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -324,7 +324,8 @@ endif()
 find_program(BUSTED_EXECUTABLE busted)
 if(BUSTED_EXECUTABLE)
     add_custom_target(check-unit ALL
-        ${BUSTED_EXECUTABLE} "--lpath=${CMAKE_BINARY_DIR}/lib/?.lua;${CMAKE_BINARY_DIR}/lib/?/init.lua;spec/?.lua"
+        ${BUSTED_EXECUTABLE} "--helper=${CMAKE_SOURCE_DIR}/spec/preload.lua"
+        "--lpath=${CMAKE_BINARY_DIR}/lib/?.lua;${CMAKE_BINARY_DIR}/lib/?/init.lua;spec/?.lua"
         WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
         COMMENT "Running unit tests"
         VERBATIM)
diff --git a/spec/preload.lua b/spec/preload.lua
new file mode 100644
index 000000000..9c5610f15
--- /dev/null
+++ b/spec/preload.lua
@@ -0,0 +1,4 @@
+-- This script is given to Busted via the --helper argument. Modules loaded here
+-- won't be cleared and reloaded by Busted. This is needed for lgi because lgi
+-- is not safe to reload and yet Busted manages to do this.
+require("lgi")