[Tkinter-discuss] Simulating keystrokes in a tkinter unit test

[alan moore]

Hi all,

I'm attempting to write a unit test for a custom widget using Python 
unittest.  I'm trying to simulate actual keystrokes in my unit test.

Following the example from the tkinter test suite, I created a test that 
is approximately this:

from tkinter import Entry as MyWidget
from tkinter.test.support import AbstractTkTest
import unittest

class TestMyWidget(AbstractTkTest, unittest.TestCase):

     def setUp(self):
         super().setUp()
         self.mywidget = self.create()
         self.mywidget.wait_visibility()

     def tearDown(self):
         super().tearDown()
         self.mywidget.destroy()

     def create(self):
         mw = MyWidget(self.root)
         mw.pack()
         return mw

     def _keystroke(self, char):
self.mywidget.event_generate('<KeyPress-{}>'.format(char))
self.mywidget.event_generate('<KeyRelease-{}>'.format(char))
         self.mywidget.update_idletasks()

     def test_key_entry(self):
         self._keystroke('a')
         self.assertEqual(self.mywidget.get(), 'a')

if __name__ == '__main__':
     unittest.main()


This doesn't work, though.  The keypresses don't register and create any 
text in the entry.  I can add text using event_generate inside a 
mainloop, but without mainloop it doesn't seem to work.


Interestingly, I can use the same method to generate mouse events and 
they seem to be recognized.  Is there a way to make keypresses work 
without mainloop?