explained unit test, used force_list option to cast to list

Author: janvanrijn

openml/tasks/functions.py

@@ -142,7 +142,7 @@ def _list_tasks(api_call):
         xml_string = _perform_api_call(api_call)
     except OpenMLServerNoResult:
         return []
-    tasks_dict = xmltodict.parse(xml_string, force_list=('oml:task',))
+    tasks_dict = xmltodict.parse(xml_string, force_list=('oml:task','oml:input'))
     # Minimalistic check if the XML is useful
     if 'oml:tasks' not in tasks_dict:
         raise ValueError('Error in return XML, does not contain "oml:runs": %s'
@@ -176,11 +176,7 @@ def _list_tasks(api_call):
                     'status': task_['oml:status']}
 
             # Other task inputs
-            task_inputs = task_.get('oml:input')
-            if isinstance(task_inputs, dict):
-                task_inputs = [task_inputs]
-
-            for input in task_inputs:
+            for input in task_.get('oml:input', list()):
                 if input['@name'] == 'estimation_procedure':
                     task[input['@name']] = proc_dict[int(input['#text'])]['name']
                 else:

tests/test_tasks/test_task_functions.py

@@ -42,11 +42,11 @@ def test__get_estimation_procedure_list(self):
         self.assertIsInstance(estimation_procedures[0], dict)
         self.assertEqual(estimation_procedures[0]['task_type_id'], 1)
 
-
     def test_list_clustering_task(self):
-        # as shown by #383, clustering tasks can give problems to server
+        # as shown by #383, clustering tasks can give list/dict casting problems
         openml.config.server = self.production_server
         openml.tasks.list_tasks(task_type_id=5, size=10)
+        # the expected outcome is that it doesn't crash. No assertions.
 
     def _check_task(self, task):
         self.assertEqual(type(task), dict)
@@ -133,7 +133,6 @@ def assert_and_raise(*args, **kwargs):
             os.path.join(os.getcwd(), "tasks", "1", "tasks.xml")
         ))
 
-
     def test_get_task_with_cache(self):
         openml.config.set_cache_directory(self.static_cache_dir)
         task = openml.tasks.get_task(1)