CreateClass: Don't shown warning about variablews when no data

Author: janezd

Orange/widgets/data/owcreateclass.py

@@ -301,7 +301,7 @@ def set_data(self, data):
         details = format_summary_details(data) if data else ""
         self.info.set_input_summary(summary, details)
         model = self.controls.attribute.model()
-        model.set_domain(data.domain if data else None)
+        model.set_domain(data.domain if data is not None else None)
         self.Warning.no_nonnumeric_vars(shown=data is not None and not model)
         if not model:
             self.attribute = None

Orange/widgets/data/tests/test_owcreateclass.py

@@ -283,6 +283,12 @@ def test_no_useful_data(self):
         self.send_signal(self.widget.Inputs.data, self.heart)
         self.assertFalse(widget.Warning.no_nonnumeric_vars.is_shown())
 
+        self.send_signal(self.widget.Inputs.data, self.heart[:0])
+        self.assertFalse(widget.Warning.no_nonnumeric_vars.is_shown())
+
+        self.send_signal(self.widget.Inputs.data, self.no_attributes[:0])
+        self.assertTrue(widget.Warning.no_nonnumeric_vars.is_shown())
+
     def test_string_data(self):
         widget = self.widget
         self.send_signal(self.widget.Inputs.data, self.zoo)