Index: trunk/tests/test_extract_waves.py
===================================================================
diff -u -r26 -r27
--- trunk/tests/test_extract_waves.py	(.../test_extract_waves.py)	(revision 26)
+++ trunk/tests/test_extract_waves.py	(.../test_extract_waves.py)	(revision 27)
@@ -44,12 +44,15 @@
 
         # 2. When
         extract_wave = extract_waves.ExtractWaves(input_data)
-        dataset_list = extract_wave.subset_era_5(dir_test_data, 1981, 1982)
+        output_data = extract_wave.subset_era_5(dir_test_data, 1981, 1982)
 
         # 3. Then
-        assert dataset_list is not None
-        assert dataset_list['variables']['swh'] is not None
+        assert output_data is not None
+        data_dict = output_data.get_data_dict()
+        assert data_dict is not None
+        assert data_dict['variables']['swh'] is not None
 
+
     @pytest.mark.systemtest
     def test_given_waves_folder_then_subset_collection_is_extracted_with_coord_list(self):
         # 1. Given