def METHOD_NAME(self):
    # Window needs to be black so that adding 2 screens doesn't make a white screen
    self.win.color = "black"
    self.win.flip()
    # Create dots
    obj = visual.DotStim(
        self.win, nDots=1,
        fieldPos=(0, 0), fieldSize=(1, 1), units="height",
        dotSize=(32, 32), dotLife=0, noiseDots='direction',
        dir=0, speed=0.25, coherence=1
    )
    # Draw dots
    obj.draw()
    # Get screenshot 1
    screen1 = np.array(self.win._getFrame(buffer="back"))
    self.win.flip()
    # Draw again, triggering position update
    obj.draw()
    # Get screenshot 2
    screen2 = np.array(self.win._getFrame(buffer="back"))
    self.win.flip()
    # Create compound screenshot with a dot in BOTH positions
    compound = np.clip(screen1 + screen2, 0, 255)
    # If dots have moved, then there should be more white on the compound screen than on either original
    assert compound.mean() > screen1.mean() and compound.mean() > screen2.mean(), (
        "Dot stimulus does not appear to have moved across two frames."