Kivy: markup label color test

lbltest.py

import kivy
kivy.require('1.9.0')

from kivy.app import App
from kivy.lang import Builder
from kivy.factory import Factory
from kivy.clock import Clock

root = Builder.load_string('''
FloatLayout:
    canvas.before:
        Color:
            rgba: 1, 1, 1, 1
        Rectangle:
            size: self.size

<TestLabel@Label>:
    font_size: 18
    size_hint_y: None
    text_size: self.width, None
    height: self.texture_size[1]
    halign: 'left'
    markup: True
    color: 0, 0, 0, 1
''')

class TestApp(App):
    def build(self):
        self.lbl = Factory.TestLabel(text='te[color=ff0000]st[/color]ing')
        root.add_widget(self.lbl)
        Clock.schedule_interval(self.update_label, 1)
        return root

    def update_label(self, dt):
        self.lbl.color = (0, 1, 0, 1) if self.lbl.color[1] == 0 else (0, 0, 0, 1)

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