diff --git a/tests/test_metabase_api.py b/tests/test_metabase_api.py
index f6d98a0..226e2b9 100644
--- a/tests/test_metabase_api.py
+++ b/tests/test_metabase_api.py
@@ -251,11 +251,22 @@ def test_search(self):
   def test_get_card_data(self):
     # json
     res = mb.get_card_data(card_id=1)
+    json_data = [
+      {'col1': 'row1 cell1', 'col2': 1},
+      {'col1': None, 'col2': 2},
+      {'col1': 'row3 cell1', 'col2': None},
+      {'col1': None, 'col2': None},
+      {'col1': 'row5 cell1', 'col2': 5}
+    ]
+    self.assertEqual(res, json_data)
+
+    # formatted rows (in json export mode, None become '' and numbers become strings, e.g. 123 -> '123')
+    res = mb.get_card_data(card_id=1, format_rows=True)
     json_data = [
       {'col1': 'row1 cell1', 'col2': '1'},
       {'col1': '', 'col2': '2'},
-      {'col1': 'row3 cell1', 'col2': None},
-      {'col1': '', 'col2': None},
+      {'col1': 'row3 cell1', 'col2': ''},
+      {'col1': '', 'col2': ''},
       {'col1': 'row5 cell1', 'col2': '5'}
     ]
     self.assertEqual(res, json_data)