AssertionError: expected '0x0000000000000000000000000000000000000000' - ethereum

Question

I am getting this error in testing my upgradeable smart contract.
I am really stuck with this can anyone help me get out of this?
contracts/StakingContract.sol
//SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
import "#openzeppelin/contracts-upgradeable/math/SafeMathUpgradeable.sol";
import "#openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import "#openzeppelin/contracts-upgradeable/utils/PausableUpgradeable.sol";
import "#openzeppelin/contracts-upgradeable/token/ERC20/ERC20Upgradeable.sol";
import "#openzeppelin/contracts-upgradeable/token/ERC20/SafeERC20Upgradeable.sol";
import "#openzeppelin/contracts-upgradeable/utils/AddressUpgradeable.sol";
import "#openzeppelin/contracts-upgradeable/utils/ReentrancyGuardUpgradeable.sol";
import "#openzeppelin/contracts-upgradeable/proxy/Initializable.sol";
contract StakingContract is ERC20Upgradeable, OwnableUpgradeable, ReentrancyGuardUpgradeable {
using SafeMathUpgradeable for uint256;
using AddressUpgradeable for address;
using SafeERC20Upgradeable for IERC20Upgradeable;
event TokensStaked(address _tokenStaker, uint256 _amount, uint256 unlockTime);
event TokenUnstaked(address _tokenStaker, uint256 _amount);
// Variable that prevents _deposit method from being called 2 times
bool private locked;
// The total staked amount
uint256 public totalStaked;
mapping (address => uint256) public stakeBalances;
mapping(address => uint256) private timestamp;
function initialize(uint256 initialSupply) public initializer {
__ERC20_init("MyToken", "TKN");
_mint(owner(), initialSupply);
}
function stakeTokens(address token, uint amount) external {
stakeBalances[msg.sender] = stakeBalances[msg.sender].add(amount);
timestamp[msg.sender] = block.timestamp.add(30 days);
require(IERC20Upgradeable(token).allowance(msg.sender, address(this)) >= amount, "Check the token allowance");
require(IERC20Upgradeable(token).transferFrom(msg.sender, address(this), amount), "Transfer failed!");
totalStaked = totalStaked.add(amount);
emit TokensStaked(msg.sender, amount, timestamp[msg.sender]);
}
function unstakeTokens(address token, uint256 amount) external nonReentrant() {
require(amount <= stakeBalances[msg.sender], "Sorry! You don't have sufficient stake balance.");
require(block.timestamp >= timestamp[msg.sender], "Sorry! you cannot withdraw tokens before your stake time.");
stakeBalances[msg.sender] = stakeBalances[msg.sender].sub(amount);
require(IERC20Upgradeable(token).transfer(msg.sender, amount));
totalStaked = totalStaked.sub(amount);
emit TokenUnstaked(msg.sender, amount);
}
function ownerWithdraw(address token) external onlyOwner() nonReentrant() {
require(IERC20Upgradeable(token).transfer(owner(), totalStaked), "Transfer Failed!");
uint256 ownerStakedBalance = stakeBalances[msg.sender];
stakeBalances[msg.sender] = stakeBalances[msg.sender].sub(ownerStakedBalance);
totalStaked = totalStaked.sub(totalStaked);
}
}
test/StakingContract.test.js
const { accounts, contract, web3 } = require('#openzeppelin/test-environment');
const { expect } = require('chai');
const { TestHelper } = require('#openzeppelin/cli');
const { Contracts, ZWeb3 } = require('#openzeppelin/upgrades');
// Import utilities from Test Helpers
const { BN, expectEvent, expectRevert } = require('#openzeppelin/test-helpers');
ZWeb3.initialize(web3.currentProvider);
const Box = Contracts.getFromLocal('StakingContract');
describe('StakingContract', function () {
const [ owner, other ] = accounts;
beforeEach(async function () {
this.project = await TestHelper();
this.proxy = await this.project.createProxy(Box);
});
it('retrieve returns a value previously stored', async function () {
// Use large integer comparisons
expect(await this.proxy.methods.owner().call()).to.equal(owner);
});
});
it gives the following error:
0 passing (864ms)
1 failing
1) StakingContract
retrieve returns a value previously stored:
AssertionError: expected '0x0000000000000000000000000000000000000000' to equal '0xA05c7D52b924DceB23a766ccB1e91e67b4aCF014'
+ expected - actual
-0x0000000000000000000000000000000000000000
+0xA05c7D52b924DceB23a766ccB1e91e67b4aCF014
I have tried to fix it with other things but the still issue persists.
Thanks in advance.