fix multi-response training essays

openassessment/xblock/data_conversion.py

@@ -95,7 +95,7 @@ def update_assessments_format(assessments):
                 if isinstance(example, dict) and isinstance(example['answer'], list) and example['answer']:
                     example['answer'] = {
                         'parts': [
-                            {'text': example['answer'][0]}
+                            {'text': example_answer} for example_answer in example['answer']
                         ]
                     }
     return assessments

openassessment/xblock/test/test_data_conversion.py

@@ -56,6 +56,7 @@ class DataConversionTest(TestCase):
     @ddt.data(
         ([{'answer': 'Ans'}], [{'answer': {'parts': [{'text': 'Ans'}]}}]),
         ([{'answer': ['Ans']}], [{'answer': {'parts': [{'text': 'Ans'}]}}]),
+        ([{'answer': ['Ans', 'Ans1']}], [{'answer': {'parts': [{'text': 'Ans'},{'text': 'Ans1'}]}}]),
         ([{'answer': []}], [{'answer': []}]),
     )
     @ddt.unpack