how to increase contract balance?

[qiluge]

this test case run failed:

    const balanceDataBefore = await contract.invokeGetMethod("my_balance", []);
    const balanceBefore = balanceDataBefore .result[0] as bigint;
contract.sendInternalMessage(
      internalMessage({ from: account1, value: BigInt(100000) })
    );
const balanceData= await contract.invokeGetMethod("my_balance", []);
    const balance = balanceData.result[0] as bigint;
    expect(balance - balanceBefore ).to.be.eq(BigInt(100000));

contract code here:

() recv_internal(int my_balance, int msg_value, cell in_msg_full, slice in_msg_body) impure {
}

int my_balance() method_id {
  [int res, cell a] = get_balance();
  return res;
}