'Check that the widget doesn\'t crash on empty data'

def test_no_data(self):

    self.send_signal(self.signal_name, self.data[:0], 1)
    self.send_signal(self.signal_name, self.data[:100], 2)
    self.send_signal(self.signal_name, self.data[50:], 3)
    for i in range(1, 4):
        self.send_signal(self.signal_name, None, i)
    self.send_signal(self.signal_name, self.data[:100], 1)
    self.send_signal(self.signal_name, self.data[:0], 1)
    self.send_signal(self.signal_name, self.data[50:], 3)
    for i in range(1, 4):
        self.send_signal(self.signal_name, None, i)
    self.send_signal(self.signal_name, self.data[:100], 1)
    self.send_signal(self.signal_name, self.data[50:], 2)
    self.send_signal(self.signal_name, self.data[:0], 3)
