在 Truffle 中测试智能合约需要：如果功能不无效，则交易恢复

Question

我正在尝试根据本文仅使用可靠性来测试智能合约的要求：

http://truffleframework.com/tutorials/testing-for-throws-in-solidity-tests

这是合约，throw代理合约和测试：

/* Testing with solidity tests. */

import "truffle/Assert.sol";
import "truffle/DeployedAddresses.sol";
import "../contracts/MyContract.sol";

contract TestMyContract {

function testInitialStoredValue() {
    MyContract mycontract = new MyContract();

    uint expected = 24;

    Assert.equal(mycontract.mynumber(), expected, "First number set should be 24.");
}

function testTheThrow() {
    MyContract mycontract = new MyContract(); 

    ThrowProxy throwproxy = new ThrowProxy(address(mycontract)); 
    uint num = 7;
    MyContract(address(throwproxy)).storeNum(num);

    bool r = throwproxy.execute.gas(200000)(); 

    Assert.isFalse(r, "Should be false because is should throw!");

}

function testNoThrow() {
    MyContract mycontract = new MyContract(); 

    ThrowProxy throwproxy = new ThrowProxy(address(mycontract)); 

    MyContract(address(throwproxy)).storeNum(22);

    bool r = throwproxy.execute.gas(200000)(); 

    Assert.isTrue(r, "Should be true because is should throw!");

}

}

// Proxy contract for testing throws
contract ThrowProxy {
  address public target;
  bytes data;

  function ThrowProxy(address _target) {
    target = _target;
  }

  //prime the data using the fallback function.
  function() {
    data = msg.data;
  }

  function execute() returns (bool) {
    return target.call(data);
  }
}

如果我运行测试，我会收到此错误：

如果我将 storeNum 函数更改为 void

 function storeNum(uint mynum)
        public
        returns (bool)
    {
     require(mynum > 10);
     mynumber = mynum; 
     return true;    
    }

到

 function storeNum(uint mynum)
        public
    {
     require(mynum > 10);
     mynumber = mynum; 
     return true;    
    }

测试有效..

有什么想法吗？

我正在使用 Truffle v4.1.11

Answer 1

让我们看看你的代码：

function storeNum(uint mynum)
        public
        returns (bool success)
    {
     require(mynum > 10);
     mynumber = mynum; 
     return true;    
    }

通过定义returns (bool success)，您对solidity 编译器说两件事：

• 有一个变量名为success，类型为bool（变量定义）
• 该变量成功将由函数返回（返回定义）

但您的变量毕竟没有返回（您的函数以 return true 结尾，这就是您在测试中收到 InvalidResponse 错误的原因。

对于您的代码，最有效的代码是：

function storeNum(uint mynum)
        public
        returns (bool)    // you should define at least the type
    {
     require(mynum > 10);
     mynumber = mynum; 
     return true;    
    }

作为练习，使用变量success的版本：

function storeNum(uint mynum)
        public
        returns (bool success)
    {
     require(mynum > 10);
     mynumber = mynum; 
     success = true;    // don't need to use return
    }

希望对你有帮助。

Answer 2

好吧，我已经向 Truffle github 提交了一个问题，它仍然处于打开状态，可能这与最近的 Solidity 更改有关：

https://github.com/trufflesuite/truffle/issues/1001

目前的解决方法是将函数包装成 void 函数并测试执行是否成功：

/*
    Contract wrapper that inherits from MyContract. This contract wraps the calls of non void functions when
    testing for exceptions.

    Why not invoke directly the function?: https://github.com/trufflesuite/truffle/issues/1001
*/

contract MyExposedContract is MyContract() {


    function callStoreNum(uint256 num)  public {
        storeNum(num);
    }

}

然后在您的测试中使用该包装器：

function testTheThrow() {
    MyExposedContract mycontract = new MyExposedContract (); 

    ThrowProxy throwproxy = new ThrowProxy(address(mycontract)); 
    uint num = 7;
    MyExposedContract (address(throwproxy)).callStoreNum(num);

    bool r = throwproxy.execute.gas(200000)(); 

    Assert.isFalse(r, "Should be false because it should throw!");

}