def METHOD_NAME(self):
    addr = self.GENESIS_ADDR
    original_balance = self.get_balance(addr)
    # send a tx to change balance
    tx = self.new_tx(value=789)
    self.send_tx(tx, True)
    # value + gas * price
    cost = 789 + self.DEFAULT_TX_FEE
    new_balance = self.get_balance(addr)
    assert_equal(original_balance - cost, new_balance)