Radviz: Enable projection for less than two selected variables

Orange/widgets/visualize/owradviz.py

@@ -275,7 +275,6 @@ class OWRadviz(OWAnchorProjectionWidget):
     graph = SettingProvider(OWRadvizGraph)
 
     class Warning(OWAnchorProjectionWidget.Warning):
-        no_features = widget.Msg("Radviz requires at least two features.")
         invalid_embedding = widget.Msg("No projection for selected features")
         removed_vars = widget.Msg("Categorical variables with more than"
                                   " two values are not shown.")
@@ -331,12 +330,6 @@ def __vizrank_set_attrs(self, attrs):
     def __model_selected_changed(self):
         self.selected_vars = [(var.name, vartype(var)) for var
                               in self.model_selected]
-
-        self.Warning.no_features.clear()
-        if len(self.model_selected) < 2:
-            self.Warning.no_features()
-            return
-
         self.init_projection()
         self.setup_plot()
         self.commit()

Orange/widgets/visualize/tests/test_owradviz.py

@@ -101,3 +101,16 @@ def test_discrete_attributes(self):
         self.assertTrue(self.widget.Warning.removed_vars.is_shown())
         self.send_signal(self.widget.Inputs.data, None)
         self.assertFalse(self.widget.Warning.removed_vars.is_shown())
+
+    def test_saved_selected_vars(self):
+        self.send_signal(self.widget.Inputs.data, self.data)
+
+        self.widget.model_selected[:] = self.data.domain[:1]
+        self.widget.variables_selection.removed.emit()
+        self.send_signal(self.widget.Inputs.data, self.data)
+        self.assertEqual(len(self.widget.model_selected[:]), 1)
+
+        self.widget.model_selected[:] = self.data.domain[:0]
+        self.widget.variables_selection.removed.emit()
+        self.send_signal(self.widget.Inputs.data, self.data)
+        self.assertEqual(len(self.widget.model_selected[:]), 4)