Lesson 7: Error: call revert exception (method="getPriceFeed()", data="0x", errorArgs=null, errorName=null, errorSignature=null, reason=null, code=CALL_EXCEPTION, version=abi/5.7.0)

[ohMySol]

Hello community, I got stuck on Lesson 7 when I was trying to execute the "Constructor" test. My contracts("FundMe" and "Price Converter") are successfully deployed, but when I write the first test and try to execute it I receive this error below:

• Error

Error: call revert exception [ See: https://links.ethers.org/v5-errors-CALL_EXCEPTION
] (method="getPriceFeed()", data="0x", errorArgs=null, errorName=null, errorSignature=null, reason=null, code=CALL_EXCEPTION, version=abi/5.7.0)

Also, I would like to the code for my tests and contracts below:

• FundMe.test.js

const { deployments, ethers, getNamedAccounts, network } = require("hardhat")
const { expect, assert } = require("chai")
const { developmentChains } = require("../../helper-hardhat-config")

!developmentChains.includes(network.name)
    ? describe.skip
    : describe("FundMe", async function () {
          let FundMe
          let deployer
          let mockV3Aggregator
          beforeEach(async () => {
              //deploy FundMe contract using Hardhat-deploy
              deployer = (await getNamedAccounts()).deployer //grab the deployer object and assign it to deployer variable
              await deployments.fixture(["all"]) // this will go through our deployment scripts, check which script has an "all" tag and deploy them to a local network
              console.log(`Your deployer is: ${deployer}`)

              FundMe = await ethers.getContractAt("FundMe", deployer) // "getContract" return the most recent deployed contract we tell it(Our example: getContract("FundMe"))
              mockV3Aggregator = await ethers.getContractAt(
                  "MockV3Aggregator",
                  deployer
              )
          })

          describe("Constructor", async function () {
              it("Set up the aggregator addresses correctly", async () => {
                  const response = await FundMe.getPriceFeed()
                  expect(response).to.equal(mockV3Aggregator.address)
              })
          })
      })

• FundMe.sol

// SPDX-License-Identifier: MIT
pragma solidity 0.8.8;

import "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";
import "./PriceConverter.sol";

error FundMe__NotOwner();

/**
 * @title A contract for crowd funding
 * @author Anton Holovchenko
 * @notice This is a sample demo funding contract
 * @dev This implements price feeds as out library
 */
contract FundMe {
    using PriceConverter for uint256;

    //State variables
    uint256 public constant MINIMUM_USD = 50 * 10**18; // 50 * 1e18
    address private immutable i_owner;
    address[] private s_funders;
    mapping(address => uint256) private s_addressToAmountFunded; //mapping for users funds
    
    AggregatorV3Interface private s_priceFeed; // This is our global variable


    modifier onlyOwner() {
        //require(msg.sender == i_owner , "Sender is not owner!");
        if (msg.sender != i_owner) {
            revert FundMe__NotOwner();
        }
        _;
    }

    constructor(address priceFeed) {
        s_priceFeed = AggregatorV3Interface(priceFeed); //priceFeed address is saved to a global AggregatorV3Interface 
        i_owner = msg.sender;
    }


    function fund() public payable {
        require(
            msg.value.getConversionRate(s_priceFeed) >= MINIMUM_USD,
            "Didn't send enougth"
        ); //1e18 == 1 * 10 ** 18 = 10000000000 or 1 ETH
        s_funders.push(msg.sender);
        s_addressToAmountFunded[msg.sender] += msg.value;
    }

    function withdraw() public onlyOwner {
        for (
            uint256 funderIndex = 0;
            funderIndex < s_funders.length;
            funderIndex++
        ) {
            address funder = s_funders[funderIndex];
            s_addressToAmountFunded[funder] = 0;
        }

        //After all adresses funds are 0, we need to reset the array
        s_funders = new address[](0); //now the funders array = new address array with 0 objects inside

        (bool success, ) = i_owner.call{value: address(this).balance}("");
        require(success); //call return us bool value if our function pass or fail
    }

    function getAddressToAmountFunded(address fundingAddress)
        public
        view
        returns (uint256)
    {
        return s_addressToAmountFunded[fundingAddress];
    }

    function getVersion() public view returns (uint256) {
        return s_priceFeed.version();
    }

    function getFunder(uint256 index) public view returns (address) {
        return s_funders[index];
    }

    function getOwner() public view returns (address) {
        return i_owner;
    }

    function getPriceFeed() public view returns (AggregatorV3Interface) {
        return s_priceFeed;
    }

    
}

• PriceConverter.sol

// SPDX-License-Identifier: MIT

pragma solidity 0.8.8;

import "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";

//if we want to use a library, we should set each function as "internal"
library PriceConverter {

    //Get the price of Eth
    function getPrice(AggregatorV3Interface priceFeed) internal view returns (uint256) {
        //  ABI
        //  Address 0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419 of ETH/USD
        //Price of ETH in terms of USD
        
        (, int256 answer, , , ) = priceFeed.latestRoundData();
        return uint256(answer * 10000000000); // or 1e10
    }

    function getConversionRate(uint256 ethAmount, AggregatorV3Interface priceFeed) internal view returns (uint256) {
        //Store here the eth price in ethPrice
        uint256 ethPrice = getPrice(priceFeed);
        //convertation of eth into usd
        uint256 ethAmountInUsd = (ethPrice * ethAmount) / 1e18; //we need to devide by 1e18 because ETH price number receive with 18 zeros
        return ethAmountInUsd;
    }
}

So I am asking for help from the community as I have no idea what is wrong with the code. Hope someone knows how to fix this :)

[Nlferu]

Hello @Antony-Holovchenko

You are just using getContract function incorrectly, so your FundMe contract is not defined as it should be.

// If you are getting contracts like below you should give the `address` parameter also

/** @dev Incorrect use:*/
FundMe = await ethers.getContractAt("FundMe", deployer)
mockV3Aggregator = await ethers.getContractAt("MockV3Aggregator", deployer)

/** @dev Correct use:*/
FundMe = await ethers.getContractAt("FundMe", deployedContractAddress, deployer)
mockV3Aggregator = await ethers.getContractAt("MockV3Aggregator", deployedContractAddress, deployer)

Or you can just use below (calling getContract instead of getContractAt):

FundMe = await ethers.getContract("FundMe", deployer)
mockV3Aggregator = await ethers.getContract("MockV3Aggregator", deployer)

[Nlferu]

Hello @Antony-Holovchenko

I have already explained you what is the difference. You are still calling contracts incorrectly as you are giving your mockV3aggregator deployed contract address for FundMe, which makes it get you wrong contract.

You should change your FundMe.test.js code as below:

              // You are pointing to FundMe contract here and then using it to get Aggregator contract, which have no sense              
              deployedContractAddress = (await deployments.get("FundMe")).address
              console.log(`Your deployer is: ${deployer}`)
              const signer = await ethers.getSigner(deployer)

              FundMe = await ethers.getContractAt(
                  "FundMe",
                  deployedContractAddress,
                  signer
              ) // "getContract" return the most recent deployed contract we tell it(Our example: getContract("FundMe"))

              /** @dev CHANGE BELOW !!! */
              mockV3Aggregator = await ethers.getContract(
                  "MockV3Aggregator",
                  deployer
              )

[ohMySol]

@Neftyr here is my updated code according your advise:

const { deployments, ethers, getNamedAccounts, network } = require("hardhat")
const { expect, assert } = require("chai")
const { developmentChains } = require("../../helper-hardhat-config")

!developmentChains.includes(network.name)
    ? describe.skip
    : describe("FundMe", function () {
          let FundMe
          let deployer
          let deployedContractAddress
          let mockV3Aggregator
          beforeEach(async () => {
              //deploy FundMe contract using Hardhat-deploy
              deployer = (await getNamedAccounts()).deployer //grab the deployer object and assign it to deployer variable
              await deployments.fixture(["all"]) // this will go through our deployment scripts, check which script has an "all" tag and deploy them to a local network
              deployedContractAddress = (await deployments.get("FundMe")).address
              console.log(`Your deployer is: ${deployer}`)
              const signer = await ethers.getSigner(deployer)

              FundMe = await ethers.getContractAt(
                  "FundMe",
                  deployedContractAddress,
                  signer
              ) // "getContract" return the most recent deployed contract we tell it(Our example: getContract("FundMe"))
              mockV3Aggregator = await ethers.getContractAt(
                  "MockV3Aggregator",
                  deployer
              )
          })

          describe("Constructor", async function () {
              it("Set up the aggregator addresses correctly", async () => {
                  const response = await FundMe.getPriceFeed()
                  expect(response).to.equal(mockV3Aggregator.address)
              })
          })
      })

but I still receive an issue that the expected result doesn't match actual.

[Nlferu]

@Antony-Holovchenko

What is output error message? If your addresses does not match try to figure out why printing everything out to console.

[ohMySol]

1. I solved this issue, congratulations! I tried copying and pasting the code from the Patric repo and then received an error(getContract() is not a function). After some research in Google I install one package -> "@nomiclabs/hardhat-ethers@npm:hardhat" and Patric code becomes working.

2. I compared my code with his code and I see that for some reason my mockV3Aggregator address takes the deployer address and this is incorrect because it should take the next address: 0x5FbDB2315678afecb367f032d93F642f64180aa3

// address of deployer: 0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266
mockV3Aggregator = await ethers.getContractAt( 
                 "MockV3Aggregator",
                 deployer
             )

I am still trying to understand where is my issue in my code.

[Nlferu]

@Antony-Holovchenko

That it exactly what I said earlier that you are getting wrong contracts and passing wrong arguments for getters functions. Your code is working for me with only above correction that I have already mentioned on my 1st reply, so you did not read it carefully if yours still throwing errors.