fix(ods): None values are not displayed as string

src/tablib/formats/_ods.py

@@ -164,6 +164,8 @@ def dset_sheet(cls, dataset, ws):
                     cell = table.TableCell(valuetype="date", datevalue=col.strftime('%Y-%m-%d'))
                 elif isinstance(col, dt.time):
                     cell = table.TableCell(valuetype="time", timevalue=col.strftime('%H:%M:%S'))
+                elif col is None:
+                    cell = table.TableCell(valuetype="void")
                 else:
                     cell = table.TableCell(valuetype="string")
                     cell.addElement(text.P(text=str(col), stylename=style))

tests/test_tablib.py

@@ -1111,9 +1111,9 @@ def test_ods_export_import_set(self):
         date = dt.date(2019, 10, 4)
         date_time = dt.datetime(2019, 10, 4, 12, 30, 8)
         time = dt.time(14, 30)
-        data.append(('string', '004', 42, 21.55, Decimal('34.5'), date, time, date_time))
+        data.append(('string', '004', 42, 21.55, Decimal('34.5'), date, time, date_time, None))
         data.headers = (
-            'string', 'start0', 'integer', 'float', 'decimal', 'date', 'time', 'date/time'
+            'string', 'start0', 'integer', 'float', 'decimal', 'date', 'time', 'date/time', 'None'
         )
         _ods = data.ods
         data.ods = _ods
@@ -1125,6 +1125,7 @@ def test_ods_export_import_set(self):
         self.assertEqual(data.dict[0]['date'], date)
         self.assertEqual(data.dict[0]['time'], time)
         self.assertEqual(data.dict[0]['date/time'], date_time)
+        self.assertEqual(data.dict[0]['None'], '')
 
     def test_ods_import_book(self):
         ods_source = Path(__file__).parent / 'files' / 'book.ods'