[ENH] OWPreprocess: data info displayed in status bar

Orange/widgets/data/owpreprocess.py

@@ -1144,6 +1144,9 @@ def mimeData(indexlist):
         box = gui.vBox(self.controlArea, "Output")
         gui.auto_send(box, self, "autocommit", box=False)
 
+        self.info.set_input_summary(self.info.NoInput)
+        self.info.set_output_summary(self.info.NoOutput)
+
         self._initialize()
 
     def _initialize(self):
@@ -1261,6 +1264,10 @@ def __on_modelchanged(self):
     def set_data(self, data=None):
         """Set the input dataset."""
         self.data = data
+        if data is not None:
+            self.info.set_input_summary(len(data))
+        else:
+            self.info.set_input_summary(self.info.NoInput)
 
     def handleNewSignals(self):
         self.apply()
@@ -1304,8 +1311,10 @@ def apply(self):
             except (ValueError, ZeroDivisionError) as e:
                 self.error(str(e))
                 return
+            self.info.set_output_summary(len(data))
         else:
             data = None
+            self.info.set_output_summary(self.info.NoOutput)
 
         self.Outputs.preprocessor.send(preprocessor)
         self.Outputs.preprocessed_data.send(data)

Orange/widgets/data/tests/test_owpreprocess.py

@@ -1,5 +1,6 @@
 # Test methods with long descriptive names can omit docstrings
-# pylint: disable=missing-docstring
+# pylint: disable=missing-docstring,unsubscriptable-object
+from unittest.mock import Mock
 import numpy as np
 
 from Orange.data import Table
@@ -12,6 +13,7 @@
 from Orange.widgets.data.owpreprocess import OWPreprocess, \
     UnivariateFeatureSelect, Scale as ScaleEditor
 from Orange.widgets.tests.base import WidgetTest, datasets
+from orangewidget.widget import StateInfo
 
 
 class TestOWPreprocess(WidgetTest):
@@ -138,6 +140,25 @@ def test_data_column_nans(self):
         self.widget.set_model(model)
         self.send_signal(self.widget.Inputs.data, table)
 
+    def test_summary(self):
+        """Check if status bar is updated when data is received"""
+        data = Table("iris")
+        input_sum = self.widget.info.set_input_summary = Mock()
+        output_sum = self.widget.info.set_output_summary = Mock()
+
+        self.send_signal(self.widget.Inputs.data, data)
+        input_sum.assert_called_with(int(StateInfo.format_number(len(data))))
+        output = self.get_output(self.widget.Outputs.preprocessed_data)
+        output_sum.assert_called_with(int(StateInfo.format_number(len(output))))
+
+        input_sum.reset_mock()
+        output_sum.reset_mock()
+        self.send_signal(self.widget.Inputs.data, None)
+        input_sum.assert_called_once()
+        self.assertEqual(input_sum.call_args[0][0].brief, "")
+        output_sum.assert_called_once()
+        self.assertEqual(output_sum.call_args[0][0].brief, "")
+
 
 # Test for editors
 class TestDiscretizeEditor(WidgetTest):