'Test discovery of notify demo platform.'

@patch('homeassistant.components.notify.demo.get_service', autospec=True)
def test_discover_notify(self, mock_demo_get_service):

    assert (notify.DOMAIN not in self.hass.config.components)
    discovery.load_platform(self.hass, 'notify', 'demo', {'test_key': 'test_val'}, {})
    self.hass.block_till_done()
    assert (notify.DOMAIN in self.hass.config.components)
    assert mock_demo_get_service.called
    assert (mock_demo_get_service.call_args[0] == (self.hass, {}, {'test_key': 'test_val'}))
