This should work

.github/workflows/ci.yml

@@ -46,7 +46,7 @@ jobs:
 
       - name: Test
         shell: msys2 {0}
-        run: timeout 2 cartridges
+        run: timeout 2 cartridges; [ "$?" -eq "124" ] && true
 
       - name: Inno Setup
         run: iscc ".\_build\Cartridges.iss"

src/main.py

@@ -21,6 +21,8 @@ import json
 import lzma
 import sys
 
+import non_existent_module
+
 import gi
 
 gi.require_version("Gtk", "4.0")