Index: trunk/tests/test_predictor_definition.py
===================================================================
diff -u -r175 -r176
--- trunk/tests/test_predictor_definition.py	(.../test_predictor_definition.py)	(revision 175)
+++ trunk/tests/test_predictor_definition.py	(.../test_predictor_definition.py)	(revision 176)
@@ -34,6 +34,8 @@
         result = PredictorDefinition.compute_spatial_gradients(data_array)
 
         assert result is not None
+        assert isinstance(result, xr.DataArray)
+        assert result.dims == data_array.dims
 
 
 class Test_ComputePCA: