[FIX] Test & Learn: handling memory error

Orange/widgets/evaluate/owtestlearners.py

@@ -217,6 +217,7 @@ class Error(OWWidget.Error):
         too_many_folds = Msg("Number of folds exceeds the data size")
         class_inconsistent = Msg("Test and train data sets "
                                  "have different target variables.")
+        memory_error = Msg("Not enough memory.")
 
     class Warning(OWWidget.Warning):
         missing_data = \
@@ -648,19 +649,23 @@ def commit(self):
         """
         Commit the results to output.
         """
+        self.Error.memory_error.clear()
         valid = [slot for slot in self.learners.values()
                  if slot.results is not None and slot.results.success]
+        combined = None
+        predictions = None
         if valid:
             # Evaluation results
             combined = results_merge([slot.results.value for slot in valid])
             combined.learner_names = [learner_name(slot.learner)
                                       for slot in valid]
 
             # Predictions & Probabilities
-            predictions = combined.get_augmented_data(combined.learner_names)
-        else:
-            combined = None
-            predictions = None
+            try:
+                predictions = combined.get_augmented_data(combined.learner_names)
+            except MemoryError:
+                self.Error.memory_error()
+
         self.Outputs.evaluations_results.send(combined)
         self.Outputs.predictions.send(predictions)
 

Orange/widgets/evaluate/tests/test_owtestlearners.py

@@ -141,6 +141,21 @@ def test_migrate_removes_invalid_contexts(self):
         self.widget.migrate_settings(settings, 2)
         self.assertEqual(settings['context_settings'], [context_valid])
 
+    def test_memory_error(self):
+        """
+        Handling memory error.
+        GH-2316
+        """
+        data = Table("iris")[::3]
+        self.send_signal("Data", data)
+        self.assertFalse(self.widget.Error.memory_error.is_shown())
+
+        with unittest.mock.patch(
+            "Orange.evaluation.testing.Results.get_augmented_data",
+            side_effect=MemoryError):
+            self.send_signal("Learner", MajorityLearner(), 0, wait=5000)
+            self.assertTrue(self.widget.Error.memory_error.is_shown())
+
 
 class TestHelpers(unittest.TestCase):
     def test_results_one_vs_rest(self):