Better batch view error reporting

graphene_django/tests/test_views.py

@@ -183,6 +183,15 @@ def test_batch_allows_post_with_json_encoding(client):
     }]
 
 
+def test_batch_fails_if_is_empty(client):
+    response = client.post(batch_url_string(), '[]', 'application/json')
+
+    assert response.status_code == 400
+    assert response_json(response) == {
+        'errors': [{'message': 'Received an empty list in the batch request.'}]
+    }
+
+
 def test_allows_sending_a_mutation_via_post(client):
     response = client.post(url_string(), j(query='mutation TestMutation { writeTest { test } }'), 'application/json')
 
@@ -432,9 +441,18 @@ def test_handles_errors_caused_by_a_lack_of_query(client):
     }
 
 
-def test_handles_invalid_json_bodies(client):
+def test_handles_not_expected_json_bodies(client):
     response = client.post(url_string(), '[]', 'application/json')
 
+    assert response.status_code == 400
+    assert response_json(response) == {
+        'errors': [{'message': 'The received data is not a valid JSON query.'}]
+    }
+
+
+def test_handles_invalid_json_bodies(client):
+    response = client.post(url_string(), '[oh}', 'application/json')
+
     assert response.status_code == 400
     assert response_json(response) == {
         'errors': [{'message': 'POST body sent invalid JSON.'}]

graphene_django/views.py

@@ -193,10 +193,19 @@ def parse_body(self, request):
             try:
                 request_json = json.loads(request.body.decode('utf-8'))
                 if self.batch:
-                    assert isinstance(request_json, list)
+                    assert isinstance(request_json, list), (
+                        'Batch requests should receive a list, but received {}.'
+                    ).format(repr(request_json))
+                    assert len(request_json) > 0, (
+                        'Received an empty list in the batch request.'
+                    )
                 else:
-                    assert isinstance(request_json, dict)
+                    assert isinstance(request_json, dict), (
+                        'The received data is not a valid JSON query.'
+                    )
                 return request_json
+            except AssertionError as e:
+                raise HttpError(HttpResponseBadRequest(str(e)))
             except:
                 raise HttpError(HttpResponseBadRequest('POST body sent invalid JSON.'))