diff --git a/xarray/tests/test_units.py b/xarray/tests/test_units.py
index d89a74e4fba..7e1105e2e5d 100644
--- a/xarray/tests/test_units.py
+++ b/xarray/tests/test_units.py
@@ -305,11 +305,13 @@ def __call__(self, obj, *args, **kwargs):
         all_args = merge_args(self.args, args)
         all_kwargs = {**self.kwargs, **kwargs}
 
+        from xarray.core.groupby import GroupBy
+
         xarray_classes = (
             xr.Variable,
             xr.DataArray,
             xr.Dataset,
-            xr.core.groupby.GroupBy,
+            GroupBy,
         )
 
         if not isinstance(obj, xarray_classes):