def setup(self):
     self.wm = WindowManager()
     self.wm.acquire('test')
class TestWindowManager:
    callback_called = False

    def setup(self):
        self.wm = WindowManager()
        self.wm.acquire('test')

    def test_add_window(self):
        self.wm.add_window('window1')
        self.wm.remove_window('window1')

    def callback(self):
        self.callback_called = True

    def test_callback(self):
        cb = lambda x: x
        self.wm.register_callback(self.callback)
        self.wm.add_window('window')
        self.wm.remove_window('window')
        assert self.callback_called

    def test_has_images(self):
        assert not self.wm.has_windows()
        self.wm.add_window('window')
        assert self.wm.has_windows()

    def teardown(self):
        self.wm._release('test')