test.py

from kivy.app import App
from kivy.factory import Factory
from kivy.config import Config


class BejotoApp(App):
    icon = 'icon.png'
    title = 'Test icon'

    def build(self):
        Config.set('kivy', 'window_icon', self.get_application_icon())
        return Factory.Button()

if __name__ == '__main__':
    BejotoApp().run()