diff --git a/tests/test_xdsl_base.py b/tests/test_xdsl_base.py
index 2dda69081a..fb966fb32f 100644
--- a/tests/test_xdsl_base.py
+++ b/tests/test_xdsl_base.py
@@ -739,7 +739,7 @@ def test_function_III():
 
     u = Function(name="u", grid=grid)
     v = TimeFunction(name="v", grid=grid)
-    w = Function(name="w", grid=grid)
+    w = TimeFunction(name="w", grid=grid)
 
     u.data[:, :] = 1.0
     v.data[:, :] = 2.0