diff --git a/django/contrib/gis/tests/geoadmin/tests.py b/django/contrib/gis/tests/geoadmin/tests.py
index 99dcdf0768..124e05b722 100644
--- a/django/contrib/gis/tests/geoadmin/tests.py
+++ b/django/contrib/gis/tests/geoadmin/tests.py
@@ -30,8 +30,7 @@ class GeoAdminTest(TestCase):
             result)
 
     def test_olmap_WMS_rendering(self):
-        admin.site.unregister(City)
-        admin.site.register(City, admin.GeoModelAdmin)
+        geoadmin = admin.GeoModelAdmin(City, admin.site)
 
         geoadmin = admin.site._registry[City]
         result = geoadmin.get_map_widget(City._meta.get_field('point'))(