def METHOD_NAME(self):
    add_new_block(self.manager, advance_clock=1)
    add_blocks_unlock_reward(self.manager)
    self.assertEqual(len(self.get_tips()), 0)
    tx = add_new_transactions(self.manager, 1, advance_clock=1)[0]
    # tx will be the tip
    self.assertCountEqual(self.get_tips(), set([tx.hash]))
    tx2 = add_new_transactions(self.manager, 1, advance_clock=1)[0]
    # tx2 will be the tip now
    self.assertCountEqual(self.get_tips(), set([tx2.hash]))
    # with a double spending tx2 must continue being the tip
    add_new_double_spending(self.manager)
    self.assertCountEqual(self.get_tips(), set([tx2.hash]))