#21940: Add unittest for WidgetRedirector. Initial patch by Saimadhav Heblikar.

Author: terryjreedy

Lib/idlelib/WidgetRedirector.py

@@ -3,19 +3,21 @@
 class WidgetRedirector:
     """Support for redirecting arbitrary widget subcommands.
 
-    Some Tk operations don't normally pass through Tkinter.  For example, if a
+    Some Tk operations don't normally pass through tkinter.  For example, if a
     character is inserted into a Text widget by pressing a key, a default Tk
     binding to the widget's 'insert' operation is activated, and the Tk library
-    processes the insert without calling back into Tkinter.
+    processes the insert without calling back into tkinter.
 
-    Although a binding to <Key> could be made via Tkinter, what we really want
-    to do is to hook the Tk 'insert' operation itself.
+    Although a binding to <Key> could be made via tkinter, what we really want
+    to do is to hook the Tk 'insert' operation itself.  For one thing, we want
+    a text.insert call in idle code to have the same effect as a key press.
 
     When a widget is instantiated, a Tcl command is created whose name is the
     same as the pathname widget._w.  This command is used to invoke the various
     widget operations, e.g. insert (for a Text widget). We are going to hook
     this command and provide a facility ('register') to intercept the widget
-    operation.
+    operation.  We will also intercept method calls on the tkinter class
+    instance that represents the tk widget.
 
     In IDLE, WidgetRedirector is used in Percolator to intercept Text
     commands.  The function being registered provides access to the top
@@ -64,9 +66,13 @@ def close(self):
     def register(self, operation, function):
         '''Return OriginalCommand(operation) after registering function.
 
-        Registration adds an instance function attribute that masks the
-        class instance method attribute. If a second function is
-        registered for the same operation, the first function is replaced.
+        Registration adds an operation: function pair to ._operations.
+        It also adds an widget function attribute that masks the tkinter
+        class instance method.  Method masking operates independently
+        from command dispatch.
+
+        If a second function is registered for the same operation, the
+        first function is replaced in both places.
         '''
         self._operations[operation] = function
         setattr(self.widget, operation, function)
@@ -80,8 +86,10 @@ def unregister(self, operation):
         if operation in self._operations:
             function = self._operations[operation]
             del self._operations[operation]
-            if hasattr(self.widget, operation):
+            try:
                 delattr(self.widget, operation)
+            except AttributeError:
+                pass
             return function
         else:
             return None
@@ -160,8 +168,7 @@ def my_insert(*args):
 
 if __name__ == "__main__":
     import unittest
-##    unittest.main('idlelib.idle_test.test_widgetredir',
-##                  verbosity=2, exit=False)
-
+    unittest.main('idlelib.idle_test.test_widgetredir',
+                  verbosity=2, exit=False)
     from idlelib.idle_test.htest import run
     run(_widget_redirector)

Lib/idlelib/idle_test/mock_idle.py

@@ -26,7 +26,10 @@ def __call__(self, *args, **kwds):
         self.called = True
         self.args = args
         self.kwds = kwds
-        return self.result
+        if isinstance(self.result, BaseException):
+            raise self.result
+        else:
+            return self.result
 
 
 class Editor:

Lib/idlelib/idle_test/test_widgetredir.py

@@ -0,0 +1,122 @@
+"""Unittest for idlelib.WidgetRedirector
+
+100% coverage
+"""
+from test.support import requires
+import unittest
+from idlelib.idle_test.mock_idle import Func
+from tkinter import Tk, Text, TclError
+from idlelib.WidgetRedirector import WidgetRedirector
+
+
+class InitCloseTest(unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        requires('gui')
+        cls.tk = Tk()
+        cls.text = Text(cls.tk)
+
+    @classmethod
+    def tearDownClass(cls):
+        cls.text.destroy()
+        cls.tk.destroy()
+        del cls.text, cls.tk
+
+    def test_init(self):
+        redir = WidgetRedirector(self.text)
+        self.assertEqual(redir.widget, self.text)
+        self.assertEqual(redir.tk, self.text.tk)
+        self.assertRaises(TclError, WidgetRedirector, self.text)
+        redir.close()  # restore self.tk, self.text
+
+    def test_close(self):
+        redir = WidgetRedirector(self.text)
+        redir.register('insert', Func)
+        redir.close()
+        self.assertEqual(redir._operations, {})
+        self.assertFalse(hasattr(self.text, 'widget'))
+
+
+class WidgetRedirectorTest(unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        requires('gui')
+        cls.tk = Tk()
+        cls.text = Text(cls.tk)
+
+    @classmethod
+    def tearDownClass(cls):
+        cls.text.destroy()
+        cls.tk.destroy()
+        del cls.text, cls.tk
+
+    def setUp(self):
+        self.redir = WidgetRedirector(self.text)
+        self.func = Func()
+        self.orig_insert = self.redir.register('insert', self.func)
+        self.text.insert('insert', 'asdf')  # leaves self.text empty
+
+    def tearDown(self):
+        self.text.delete('1.0', 'end')
+        self.redir.close()
+
+    def test_repr(self):  # partly for 100% coverage
+        self.assertIn('Redirector', repr(self.redir))
+        self.assertIn('Original', repr(self.orig_insert))
+
+    def test_register(self):
+        self.assertEqual(self.text.get('1.0', 'end'), '\n')
+        self.assertEqual(self.func.args, ('insert', 'asdf'))
+        self.assertIn('insert', self.redir._operations)
+        self.assertIn('insert', self.text.__dict__)
+        self.assertEqual(self.text.insert, self.func)
+
+    def test_original_command(self):
+        self.assertEqual(self.orig_insert.operation, 'insert')
+        self.assertEqual(self.orig_insert.tk_call, self.text.tk.call)
+        self.orig_insert('insert', 'asdf')
+        self.assertEqual(self.text.get('1.0', 'end'), 'asdf\n')
+
+    def test_unregister(self):
+        self.assertIsNone(self.redir.unregister('invalid operation name'))
+        self.assertEqual(self.redir.unregister('insert'), self.func)
+        self.assertNotIn('insert', self.redir._operations)
+        self.assertNotIn('insert', self.text.__dict__)
+
+    def test_unregister_no_attribute(self):
+        del self.text.insert
+        self.assertEqual(self.redir.unregister('insert'), self.func)
+
+    def test_dispatch_intercept(self):
+        self.func.__init__(True)
+        self.assertTrue(self.redir.dispatch('insert', False))
+        self.assertFalse(self.func.args[0])
+
+    def test_dispatch_bypass(self):
+        self.orig_insert('insert', 'asdf')
+        # tk.call returns '' where Python would return None
+        self.assertEqual(self.redir.dispatch('delete', '1.0', 'end'), '')
+        self.assertEqual(self.text.get('1.0', 'end'), '\n')
+
+    def test_dispatch_error(self):
+        self.func.__init__(TclError())
+        self.assertEqual(self.redir.dispatch('insert', False), '')
+        self.assertEqual(self.redir.dispatch('invalid'), '')
+
+    def test_command_dispatch(self):
+        # Test that .__init__ causes redirection of tk calls
+        # through redir.dispatch
+        self.tk.call(self.text._w, 'insert', 'hello')
+        self.assertEqual(self.func.args, ('hello',))
+        self.assertEqual(self.text.get('1.0', 'end'), '\n')
+        # Ensure that called through redir .dispatch and not through
+        # self.text.insert by having mock raise TclError.
+        self.func.__init__(TclError())
+        self.assertEqual(self.tk.call(self.text._w, 'insert', 'boo'), '')
+
+
+
+if __name__ == '__main__':
+    unittest.main(verbosity=2)