diff --git a/tests/cpydiff/core_function_moduleattr.py b/tests/cpydiff/core_function_moduleattr.py
new file mode 100644
index 0000000000..71747c1f40
--- /dev/null
+++ b/tests/cpydiff/core_function_moduleattr.py
@@ -0,0 +1,13 @@
+"""
+categories: Core,Functions
+description: Function objects do not have the ``__module__`` attribute
+cause: MicroPython is optimized for reduced code size and RAM usage.
+workaround: Use ``sys.modules[function.__globals__['__name__']]`` for non-builtin modules.
+"""
+
+
+def f():
+    pass
+
+
+print(f.__module__)