Merge pull request #4631 from janezd/pytablemodel-wrap-empty

[FIX] PyTableModel: Allow wrapping empty lists

Author: ales-erjavec

Orange/widgets/utils/itemmodels.py

@@ -107,7 +107,9 @@ def __init__(self, sequence=None, parent=None, editable=False):
         self._editable = editable
         self._table = None
         self._roleData = {}
-        self.wrap(sequence or [])
+        if sequence is None:
+            sequence = []
+        self.wrap(sequence)
 
     def rowCount(self, parent=QModelIndex()):
         return 0 if parent.isValid() else self._rows

Orange/widgets/utils/tests/test_itemmodels.py

@@ -42,6 +42,14 @@ def test_init(self):
         self.model = PyTableModel()
         self.assertEqual(self.model.rowCount(), 0)
 
+    def test_init_wrap_empty(self):
+        # pylint: disable=protected-access
+        t = []
+        model = PyTableModel(t)
+        self.assertIs(model._table, t)
+        t.append([1, 2, 3])
+        self.assertEqual(list(model), [[1, 2, 3]])
+
     def test_rowCount(self):
         self.assertEqual(self.model.rowCount(), 2)
         self.assertEqual(len(self.model), 2)