Error in Truffle test

General
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1

I am creating DEX I have been getting error while testing my smart contracts

My Smart contract


  pragma solidity 0.8.6;

import "./Saubaan_2.sol";

contract  MySwap {
    string public name = "MySwap Ultimate Exchange";
    Saubaan_2 public token;
    uint public rate = 100;

    event TokenPurchased(
        address  account,
        address token,
        uint amount,
        uint rate
         
    ); 
  
 function buyTokens(address) public  payable  {
     // Calculate the number of tokens to buy
     uint tokenAmount = msg.value*rate;

     // Require that myswap has enough tokens
    require(token.balanceOf(address(this)) >= tokenAmount);
    // Transfer tokens to the user
     token.transfer(msg.sender, tokenAmount );

    // Emit an event
     emit TokenPurchased(msg.sender, address(token), tokenAmount, rate);

 }

My Test.js file

    const { assert } = require('chai');
const Saubaan_2= artifacts.require("Saubaan_2");
const MySwap = artifacts.require("MySwap");
require('chai')
 .use(require('chai-as-promised'))
 .should()
function tokens(n){
    return web3.utils.toWei(n, 'ether');
}

   contract('MySwap', (accounts) => {
       let token, myswap
    before(async() =>{
        token = await Saubaan_2.new()
         myswap = await MySwap.new()
         await token.transfer(myswap.address, tokens('1000000') )  
     })
     describe('Saubaan_2 deployment', async() => {
        it('contract has a name', async() => { 
            const name = await token.name()
            assert.equal(name , 'Saubaan 2')        
        })
    })
    
    describe('MySwap deployment', async() => {
        it('contract has a name', async() => {       
            const name = await myswap.name()
            assert.equal(name , 'MySwap Ultimate Exchange')              
     })
     it('contract has tokens', async() => {
       
        let balance = await token.balanceOf(myswap.address)
        assert.equal(balance.toString(),  tokens('1000000'))
   
        
       })
   
    })
    describe ('buyTokens()', async() => {
        let result 
        before( async() => {
            // pUrchase tokens before each example
           result = await myswap.buyTokens({from: accounts[1], value: web3.utils.toWei('1', 'ether')  })
        })
        it('Allows user to instantly buy tokens from myswap for a fixed price ',async() => {
            let investorBalance = await token.balanceOf(investor)
            assert.equal(investorBalance.toString(), tokens('100'))
            // Check myswap balance after purchase
            let myswapBalance 
            myswapBalance = await token.balanceOf(myswap.address)
            assert.equal(myswapBalance.toString(), tokens('99900'))
            myswapbalance = await web3.eth.getBalance(myswap.address)
            assert.equal(myswapBalance.toString(), web3.utils.toWei('1', 'ether')) 
           
        })

    })


    })

Now the error is occuring after this line
result = await myswap.buyTokens({from: accounts[1], value: web3.utils.toWei('1', 'ether') })
If I comment out the above line my test is running fine.

Error shown after truffle test

1) Contract: MySwap
     buyTokens()
       "before all" hook for "Allows user to instantly buy tokens from myswap for a fixed price ":
   Error: Returned error: VM Exception while processing transaction: revert
    at Context.<anonymous> (test\MySwap.test.js:44:34)
    at processImmediate (internal/timers.js:464:21)

please help me I Want to become a good blockchain developer
Thanks in advance

2

Hi, welcome! :wave:

It looks like ok, so could you please share the code of the Saubaan_2.sol?

3

ok This is the code for Saubaan_2.sol

pragma solidity 0.8.6;

contract Saubaan_2 {
    string  public name = "Saubaan 2";
    string  public symbol = "SBN";
    uint256 public decimals = 18 ;
    uint256 public totalSupply = 1000000000000000000000000;

    event Transfer(
        address indexed _from,
        address indexed _to,
        uint256 _value
    );

    event Approval(
        address indexed _owner,
        address indexed _spender,
        uint256 _value
    );

    mapping(address => uint256) public balanceOf;
    mapping(address => mapping(address => uint256)) public allowance;

    constructor() {
        balanceOf[msg.sender] = totalSupply;
    }

    function transfer(address _to, uint256 _value) public returns (bool success) {
        require(balanceOf[msg.sender] >= _value);

        balanceOf[msg.sender] -= _value;
        balanceOf[_to] += _value;

       emit Transfer(msg.sender, _to, _value);

        return true;
    }

    function approve(address _spender, uint256 _value) public returns (bool success) {
        allowance[msg.sender][_spender] = _value;

       emit Approval(msg.sender, _spender, _value);

        return true;
    }

    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
        require(_value <= balanceOf[_from]);
        require(_value <= allowance[_from][msg.sender]);

        balanceOf[_from] -= _value;
        balanceOf[_to] += _value;

        allowance[_from][msg.sender] -= _value;

       emit Transfer(_from, _to, _value);

        return true;
    }
}

Thanks for replying sir pls help me I want to become a good dveloper

4

SIr you did not reply me

5

code
code2480×860 226 KB

7

What do you mean by this sir??

8

Variable investor haven't been declared anywhere above that why the line below failed

9

Thanks sir this helped

10

Thank sir for your help I solved the error

If you Don’t mind Can you please help me become a blockchain developer I am new to this stuff. I want to become a good developer.

I would like very much to be personally in contact with you.

Thank you very much sir.

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