def test_build_event(self):
        evt = event.build_event("evt_name", arg1="val1", arg2=None)
        assert evt.name == "evt_name"
        assert evt.args == {'arg1': "val1", 'arg2': None}
def voltage(title, pos, voltage, ax=0):
    """plot voltage vs. position"""
    if ax == 0:
        ax = plt.gca()
    ax.set_title('{} / V'.format(title))
    ax.grid(True)
    ax.plot(pos, voltage)