Here is my smart contract source code.

// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.9;

contract CampaignFactory {
  address[] public deployedCampaigns;

  function createCampaign(uint minimum) public {
     Campaign newCompaign  = new Campaign(minimum, msg.sender);

  function getDeployedCampaigns() public view returns(address[] memory){
     return deployedCampaigns;


contract Campaign {

  struct Request {
    string description;
    uint amount;
    address recipient;
    bool complete;
    uint approvalCount;
    mapping (address => bool) approvals;
  mapping(address => bool) approvers;
  uint approversCount;
  Request[] requests;

  address public manager;
  uint public minimumContribution;

  modifier restricted() {
    require(msg.sender == manager);
  constructor(uint minimum, address creator) {
    manager = creator;
    minimumContribution = minimum;

  function contribute() public payable {
    require(msg.value > minimumContribution);
    approvers[msg.sender] = true;

  function createRequest(string memory description, uint amount, address recipient) public 

     Request storage newRequest = requests.push();
     newRequest.description = description;
     newRequest.amount = amount;
     newRequest.recipient = recipient;
     newRequest.complete = false;
     newRequest.approvalCount = 0;    

Truffle javascript test code :

const {assert} = require('chai');
const Web3 = require('web3');
const ganache = require('ganache-cli');
const web3 = new Web3(ganache.provider());

const CampaignFactory = artifacts.require('./CampaignFactory');
const Campaign = artifacts.require('./Campaign');

contract('CampaignFactory', (accounts) => {
  let factory;
  let campaign;
  let campaignAddress;

  before( async () => {
    factory = await CampaignFactory.deployed();   

    // We create a campaign instance but not get a reference to the campaign instance.
    // Remember that anytime we send a transaction we get absolutely no result back except for 
    // a transaction receipt
    const childContractTx = await factory.createCampaign(web3.utils.toWei('0.02', 'ether'));
    campaignAddress = childContractTx.receipt.to;        
    campaign = await Campaign.at(campaignAddress);     
  describe('CampaignFactory deployment', async () =>{
    it('successfully deployed', async () => {
      const address = await factory.address 
      assert.notEqual(address, '')
      assert.notEqual(address, null)
      assert.notEqual(address, undefined)
      assert.notEqual(address, 0x0)

    it('successfully created a campaign', async ()=> {
      const address = await campaign.address;     
      assert.notEqual(address, '')
      assert.notEqual(address, null)
      assert.notEqual(address, undefined)
      assert.notEqual(address, 0x0)      

  describe('Campaign', async ()=> {    
    it('contribute', async ()=> {                   
      const manager = await campaign.manager();
      console.log("manager", manager)
      assert.equal(accounts[0], manager);

The below is the result of test : enter image description here

The "Campaign" instance was created and deployed by CampaignFactory. "manager" is a public state variable of "Campaign" smart contract. So I tried to read it through its default getter. But it was failed. What's wrong with me?

1 Answer 1


The problem is in this line:

campaignAddress = childContractTx.receipt.to; 

the transaction of the following line is executing the function createCampaign of the factory smart contract

 const childContractTx = await factory.createCampaign(web3.utils.toWei('0.02', 'ether'));

so the value of childContractTx.receipt.to is the address of factory contract and not the campaign contract address

you should use something like this:

campaignAddress = await factory.deployedCampaigns(0);
campaign = await Campaign.at(campaignAddress); 

since the function createCampaign is storing the address in the array: deployedCampaigns

in this line of your smart contract:


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