如何用 hardhat 去测试fallback函数？

合约代码：

//SPDX-License-Identifier: Unlicense
pragma solidity ^0.8.0;

import "hardhat/console.sol";

contract Greeter {

    string private greeting;

    event Log(uint gas);

    constructor() {

    }


    fallback() external payable {
        console.log("hello", "");
        emit Log(gasleft());
    }

    receive() external payable {
    }


}

js调用的代码：

const Greeter = await ethers.getContractFactory("Greeter");
    const greeter = await Greeter.deploy();
    await greeter.deployed();

    const tx = await greeter.abc();

错误提示：greeter.abc is not a function

反正就是我调用了智能合约里面没有的函数，就会报错的。