Lesson 7 : brownie.exceptions.VirtualMachineError: revert

[Krishduttm]

Brownie v1.17.2 - Python development framework for Ethereum

==================================================== test session starts ====================================================
platform darwin -- Python 3.9.5, pytest-6.2.5, py-1.11.0, pluggy-1.0.0
rootdir: /Users/apple/Desktop/web3/Brownie/brownie-smart-lottery_
plugins: eth-brownie-1.17.2, xdist-1.34.0, hypothesis-6.27.3, web3-5.25.0, forked-1.3.0
collected 1 item                                                                                                            

Launching 'ganache-cli --accounts 10 --fork https://eth-rinkeby.alchemyapi.io/v2/OzP_8l22Ebcxi4UKfbsX40aGnCcfPD65 --mnemonic brownie --port 8545 --hardfork istanbul'...

tests/test_lottery.py F                                                                                               [100%]

========================================================= FAILURES ==========================================================
_________________________________________________ test_Lottery_entranceFee __________________________________________________

    def test_Lottery_entranceFee():
    
        account = accounts[0]
        lottery = Lottery.deploy(
            config["networks"][network.show_active()]["eth_usd_price_feed"],
            {"from": account},
        )
>       assert lottery.getEntranceFee() < 2000000000000000
E       brownie.exceptions.VirtualMachineError: revert

tests/test_lottery.py:12: VirtualMachineError
================================================== short test summary info ==================================================
FAILED tests/test_lottery.py::test_Lottery_entranceFee - brownie.exceptions.VirtualMachineError: revert
===================================================== 1 failed in 7.07s =====================================================

what is the problem?

My brownie-config.yaml -

test-file -

contract file -

[cromewar]

Hello @Krishduttm
Could you run the test again but using -s identifier.

brownie test -s -k tes_name --network network_name

[sheahwen]

Hi @cromewar
I have the exact same issue as @Krishduttm. Same test function and setup. I have ran the test again using
brownie test -s -k test_get_entrance_fee --network mainnet-fork

I am currently following Patrick's code till 6:29:27. Appreciate if you could help me with the issue. Thanks!

[Krishduttm]

Can you share your test file code and contract file? Thanks

[sheahwen]

Following are my codes. Brownie compile works perfectly. I have upgraded to brownie version18 as suggested by @n4n0b1t3 but still having the same error.

Lottery.sol

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.9.0;

import "@chainlink/contracts/src/v0.6/interfaces/AggregatorV3Interface.sol";

contract Lottery {
    address payable[] public players;
    uint256 public usdEntryFee;
    AggregatorV3Interface internal ethUsdPriceFeed;

    constructor(address _priceFeedAddress) public {
        usdEntryFee = 50 * (10**18);
        ethUsdPriceFeed = AggregatorV3Interface(_priceFeedAddress);
    }
    
    function enter() public payable {
        // minimum USD$50
        // require();
        players.push(msg.sender);
    }
    function getEntranceFee() public view returns (uint256) {
        (,int256 price,,,) = ethUsdPriceFeed.latestRoundData();
        // $50 => $50/ETH
        uint256 adjustedPrice = uint256(price) * 10 **10; // 18 decimals
        uint256 costToEnter = (usdEntryFee * 10 ** 18) / adjustedPrice;
        return costToEnter;
    }
    function startLottery() public {}
    function endLottery() public {}
}

test_lottery.py

from brownie import Lottery, accounts, config, network


def test_get_entrance_fee():
    account = accounts[0]
    lottery = Lottery.deploy(
        config["networks"][network.show_active()]["eth_usd_price_feed"],
        {"from": account},
    )
    assert lottery.getEntranceFee() > 1000

brownie-config.yaml

dependencies:
  - smartcontractkit/chainlink-brownie-contracts@1.1.1
compiler:
  solc:
    remappings:
      - "@chainlink=smartcontractkit/chainlink-brownie-contracts@1.1.1"
networks:
  mainnet-fork:
    eth_usd_price_feed: "0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419"

[cromewar]

For me the problem is due to a bad configuration on the network
Please delete mainnet-fork and add it again, being sure to not have a type and typing correctly the host name

[n4n0b1t3]

when walking backward from your error through your code I come to only one transaction which can revert.

Since you are using the mainnet-fork, try to dissect your code by opening a new *.py file and only use the minimum code necessary to test the correct workings of the AggregatorV3Interface(_priceFeedAddress) transaction.

I also noticed that you have an outdated Brownie version. The current version is 1.18.1.
Please look at: #1110
and: #1109

The whole setup might be a little cumbersome the first time, but you can eliminate a lot of potential errors which have nothing to do with your code, by just implementing this approach.

[jslim89]

Hi, I'm having the same issue, has been stuck for days

Python: v3.8
Brownie v1.18.1
solidity: ^0.8.0;
smartcontractkit/chainlink-brownie-contracts@1.2.0

I've tried both Alchemy & Infura, tried Python 3.8 & 3.9, tried Solidity 0.6.6 & 0.8.0, tried both http & wss in the fork, all not working

brownie networks add Development mainnet-fork cmd=ganache-cli host=http://ganache-cli fork=https://mainnet.infura.io/v3/apikey accounts=10 mnemonic=brownie port=8545
brownie networks add Development mainnet-fork cmd=ganache-cli host=http://ganache-cli fork='wss://eth-mainnet.alchemyapi.io/v2/apikey' accounts=10 mnemonic=brownie port=8545

Anything else I might possibly miss?

[cromewar]

Did you guys @jslim89 @dRoysch deleted the default mainnet-fork network before adding the new one? also have you configured the infura/alchemy on the correct networks?

[jslim89]

Hi @cromewar Yes, I have deleted the existing mainnet-fork, otherwise it will not be allowed to add another one.

The Alchemy config

[dRoysch]

Hi!

I fix the problem by closing Ganache.

I saw the error because when I ganache-cli into the console
Throw this error
Ganache CLI v6.12.2 (ganache-core: 2.13.2) Error: listen EADDRINUSE: address already in use 127.0.0.1:8545 at Server.setupListenHandle [as _listen2] (net.js:1301:14) at listenInCluster (net.js:1349:12) at doListen (net.js:1488:7) at processTicksAndRejections (internal/process/task_queues.js:81:21)

Note: when command brownie test --network mainnet-fork the contract was deployed to Ganache GUI.

Thanks you a lot!

[cromewar]

I'm glad is solved now.