VM Exception while processing transaction revert

General
1

Hi,
I have two smart contracts (SCs): sender and receiver and a tester. I am using truffle test. I don't know how to send Ether to a SC using truffle test. The sender has no Ether balance. Maybe this is the reason, I am getting VM error:

pragma solidity ^0.5.8;

contract sender{
   address owner;
constructor () public{
   owner = msg.sender;
}

function transferTo(address to, uint amount) public{
   (bool success,) = to.call.value(amount)("");
   require (success);
}
function() external payable{}
}

Following is my receiver:

pragma solidity ^0.5.8;
contract receiver{
   address public owner;
   mapping(address => uint) public balance; 
constructor () public{
   owner = msg.sender;
}
function() external payable{
   balance[owner] += msg.value;}
}

Following is my tester:


pragma solidity ^0.5.8;
import "truffle/Assert.sol";
import "../contracts/sender.sol";
import "../contracts/receiver.sol";
contract TestTransfer{
   function testTransfer() public{
      sender senderObj = new sender();
      receiver receiverObj = new receiver();
      senderObj.transferTo(msg.sender, 10);
      Assert.equal(receiverObj.balance(receiverObj.owner()), 10, "Received amount is not correct");
   }
}

Output says that my test fails and displays an error message.

The output and the error message is given below:

TestTransfer
    1) testTransfer
    > No events were emitted


  0 passing (5s)
  1 failing

  1) TestTransfer
       testTransfer:
     Error: Returned error: VM Exception while processing transaction: revert
      at Context.TestCase (/home/zulfi/.nvm/versions/node/v10.23.3/lib/node_modules/truffle/build/webpack:/packages/core/lib/testing/SolidityTest.js:92:1)
      at process._tickCallback (internal/process/next_tick.js:68:7)

Somebody please guide me. Maybe sender does not have any Ether.
Zulfi.

2

Hey, I think there is no Ether in the sender contract when you call testTransfer to make a new one, so maybe you can change your code like this:

function testTransfer() public payable{
      sender senderObj = new sender();
      address(senderObj).transfer(msg.value); // <<<--- add this line to transfer some ETH
      receiver receiverObj = new receiver();
      senderObj.transferTo(msg.sender, 10);
      //Assert.equal(receiverObj.balance(msg.sender)), 10, "Received amount is not correct"); 
}

If Alice calls testTransfer, she is the msg.sender, and in this function, it creates two new contracts, so for these two contracts, msg.sender is the contract TestTransfer , so if the sender contract has ether, and when it executes senderObj.transferTo(msg.sender, 10);, the caller(Alice) should get 10 wei.

1 Like
3

Hi my friend,
Thanks for your response. Actually, I am executing "Truffle test". testTransfer is the function of TestTransfer, so it will execute. No body is calling testTransfer() except "Truffle test". Your changes are giving the same error.

$ truffle test
Using network 'development'.


Compiling your contracts...
===========================
> Compiling ./test/testingTransfer.sol
> Artifacts written to /tmp/test--9488-EXBU1Pcl3Vyp
> Compiled successfully using:
   - solc: 0.5.16+commit.9c3226ce.Emscripten.clang



  TestTransfer
    1) testTransfer

> No events were emitted

0 passing (6s)
1 failing

  1. TestTransfer
    testTransfer:
    Error: Returned error: VM Exception while processing transaction: revert
    at Context.TestCase (testing/SolidityTest.js:92:1)
    at process._tickCallback (internal/process/next_tick.js:68:7)

Somebody please guide me.

Zulfi.