Solidity，摩卡断言错误：未指定的断言错误

如何解决Solidity，摩卡断言错误：未指定的断言错误

我正在学习如何使用 mocha 对 solidity 代码进行单元测试，我从简单的代码中得到了这个错误：

contract hello{
    function returnString() public pure returns(string memory){
        return "this";
    }
}

在没有 try/catch 的情况下进行测试时：

const Hello = artifacts.require('hello');

contract('hello',() => {

    it('should return string',async () => {
        const hello = await Hello.deployed();
        const result = hello.returnString();
        assert(result == "this");
    });
});

我收到此错误：

  Contract: hello
    1) should return string
    > No events were emitted


  0 passing (291ms)
  1 failing

  1) Contract: hello
       should return string:
     AssertionError: Unspecified AssertionError
      at Context.<anonymous> (test/Hello.js:15:3)
      at processticksAndRejections (node:internal/process/task_queues:94:5)

但是当我用 try/catch 测试它时：

const Hello = artifacts.require('hello');

contract('hello',() => {
    it('should return string',async () => {
        const hello = await Hello.deployed();
        const result = hello.returnString();
        
        try { 
            assert(result === "this");
        }
        catch (e){
            console.log(e);
        }
        
    });
});

我得到了这个：（✓ should return string 是绿色的，表示它通过了测试）

  Contract: hello
AssertionError: Unspecified AssertionError
    at Context.<anonymous> (/home/kaneda/Documents/learn/testing/contract_1/test/Hello.js:18:4)
    at processticksAndRejections (node:internal/process/task_queues:94:5) {
  showDiff: false,actual: null,expected: undefined
}
    ✓ should return string


  1 passing (143ms)

那么，这种行为是什么，它实际上是通过测试但抛出错误还是什么？我有点糊涂了。

解决方法

哦，愚蠢的错误，我在await之前忘记了hello.returnString()

const result = hello.returnString();

这解释了代码失败的原因，但我仍然不理解 try/catch 行为。