diff --git a/tests/frame/test_group.py b/tests/frame/test_group.py
index 8ee0dd1..ac61169 100644
--- a/tests/frame/test_group.py
+++ b/tests/frame/test_group.py
@@ -51,6 +51,7 @@ def test_group_updateorder():
         f.updater = ["x", "z"]
     f.updater = ["y", "x"]
     assert f.updateorder == ["y", "x"]
+    assert repr(f.updater.updater._func) == "list_updater"
 
     def upd_x(f):
         return f.x * f.y
diff --git a/tests/frame/test_updater.py b/tests/frame/test_updater.py
index aa93fa9..251648f 100644
--- a/tests/frame/test_updater.py
+++ b/tests/frame/test_updater.py
@@ -1,6 +1,7 @@
 # Tests for Updater class
 
 
+from simframe.frame.frame import Frame
 from simframe.frame import Updater
 
 
@@ -8,3 +9,12 @@ def test_updater_repr_str():
     upd = Updater()
     assert isinstance(repr(upd), str)
     assert isinstance(str(upd), str)
+
+    f = Frame()
+
+    def func(f):
+        pass
+
+    f.updater = func
+    assert isinstance(repr(f.updater.updater), str)
+    assert isinstance(str(f.updater.updater), str)