Issue #21694: Add unittest for ParenMatch. Patch by Saimadhav Heblikar.

Lib/idlelib/ParenMatch.py

@@ -90,7 +90,8 @@ class ParenMatch:
             self.set_timeout = self.set_timeout_none
 
     def flash_paren_event(self, event):
-        indices = HyperParser(self.editwin, "insert").get_surrounding_brackets()
+        indices = (HyperParser(self.editwin, "insert")
+                   .get_surrounding_brackets())
         if indices is None:
             self.warn_mismatched()
             return
@@ -167,6 +168,11 @@ class ParenMatch:
         # associate a counter with an event; only disable the "paren"
         # tag if the event is for the most recent timer.
         self.counter += 1
-        self.editwin.text_frame.after(self.FLASH_DELAY,
-                                      lambda self=self, c=self.counter: \
-                                      self.handle_restore_timer(c))
+        self.editwin.text_frame.after(
+            self.FLASH_DELAY,
+            lambda self=self, c=self.counter: self.handle_restore_timer(c))
+
+
+if __name__ == '__main__':
+    import unittest
+    unittest.main('idlelib.idle_test.test_parenmatch', verbosity=2)

Lib/idlelib/idle_test/test_parenmatch.py

+"""Test idlelib.ParenMatch."""
+# This must currently be a gui test because ParenMatch methods use
+# several text methods not defined on idlelib.idle_test.mock_tk.Text.
+
+import unittest
+from unittest.mock import Mock
+from test.support import requires
+from tkinter import Tk, Text
+from idlelib.ParenMatch import ParenMatch
+
+class DummyEditwin:
+    def __init__(self, text):
+        self.text = text
+        self.indentwidth = 8
+        self.tabwidth = 8
+        self.context_use_ps1 = True
+
+
+class ParenMatchTest(unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        requires('gui')
+        cls.root = Tk()
+        cls.text = Text(cls.root)
+        cls.editwin = DummyEditwin(cls.text)
+        cls.editwin.text_frame = Mock()
+
+    @classmethod
+    def tearDownClass(cls):
+        del cls.text, cls.editwin
+        cls.root.destroy()
+        del cls.root
+
+    def tearDown(self):
+        self.text.delete('1.0', 'end')
+
+    def test_paren_expression(self):
+        """
+        Test ParenMatch with 'expression' style.
+        """
+        text = self.text
+        pm = ParenMatch(self.editwin)
+        pm.set_style('expression')
+
+        text.insert('insert', 'def foobar(a, b')
+        pm.flash_paren_event('event')
+        self.assertIn('<<parenmatch-check-restore>>', text.event_info())
+        self.assertTupleEqual(text.tag_prevrange('paren', 'end'),
+                             ('1.10', '1.15'))
+        text.insert('insert', ')')
+        pm.restore_event()
+        self.assertNotIn('<<parenmatch-check-restore>>', text.event_info())
+        self.assertEqual(text.tag_prevrange('paren', 'end'), ())
+
+        # paren_closed_event can only be tested as below
+        pm.paren_closed_event('event')
+        self.assertTupleEqual(text.tag_prevrange('paren', 'end'),
+                                                ('1.10', '1.16'))
+
+    def test_paren_default(self):
+        """
+        Test ParenMatch with 'default' style.
+        """
+        text = self.text
+        pm = ParenMatch(self.editwin)
+        pm.set_style('default')
+
+        text.insert('insert', 'def foobar(a, b')
+        pm.flash_paren_event('event')
+        self.assertIn('<<parenmatch-check-restore>>', text.event_info())
+        self.assertTupleEqual(text.tag_prevrange('paren', 'end'),
+                             ('1.10', '1.11'))
+        text.insert('insert', ')')
+        pm.restore_event()
+        self.assertNotIn('<<parenmatch-check-restore>>', text.event_info())
+        self.assertEqual(text.tag_prevrange('paren', 'end'), ())
+
+    def test_paren_corner(self):
+        """
+        Test corner cases in flash_paren_event and paren_closed_event.
+
+        These cases force conditional expression and alternate paths.
+        """
+        text = self.text
+        pm = ParenMatch(self.editwin)
+
+        text.insert('insert', '# this is a commen)')
+        self.assertIsNone(pm.paren_closed_event('event'))
+
+        text.insert('insert', '\ndef')
+        self.assertIsNone(pm.flash_paren_event('event'))
+        self.assertIsNone(pm.paren_closed_event('event'))
+
+        text.insert('insert', ' a, *arg)')
+        self.assertIsNone(pm.paren_closed_event('event'))
+
+    def test_handle_restore_timer(self):
+        pm = ParenMatch(self.editwin)
+        pm.restore_event = Mock()
+        pm.handle_restore_timer(0)
+        self.assertTrue(pm.restore_event.called)
+        pm.restore_event.reset_mock()
+        pm.handle_restore_timer(1)
+        self.assertFalse(pm.restore_event.called)
+
+
+if __name__ == '__main__':
+    unittest.main(verbosity=2)