diff --git a/test/core/gridmapping/test_base.py b/test/core/gridmapping/test_base.py
index c757880fe..8b4241dba 100644
--- a/test/core/gridmapping/test_base.py
+++ b/test/core/gridmapping/test_base.py
@@ -264,6 +264,7 @@ def test_scale(self):
     def test_transform(self):
         gm = TestGridMapping(**self.kwargs(xy_min=(20, 56),
                                            size=(400, 200),
+                                           tile_size=(400, 200),
                                            xy_res=(0.01, 0.01)))
         transformed_gm = gm.transform('EPSG:32633')