Unable to filter events with specific values of indexed parameters

Question

I am currently trying to test a smart contract using the truffle suit ( with 'truffle test'). My contract is of a simple ERC20 token which includes the standard Transfer event:

event Transfer(address indexed from, address indexed to, uint256 value);

Below is my code which attempts to subscribe to all "Transfer" events only coming from account[0] to account[1]. Even though the 2 parameters are declared as "indexed", the filter does not seem to work and I get all Transfer events no matter the sender/receiver. I tried modifying the code in various ways but nothing seems to work so far

const EnergyToken = artifacts.require("EnergyToken");
const assert = require('assert');
const truffleAssert = require('truffle-assertions');
const { performance } = require('perf_hooks');

contract("Energy Heavy Load Test", async accounts => {
    const numberOfTransactions = 10;
    let startTime = 0;
    let finishTime = 0;
    let subscription;
    let contract;
    let i = 0;

    console.log(web3.version);

    // Function for rounding numbers
    function round(value, precision) {
        var multiplier = Math.pow(10, precision || 0);
        return Math.round(value * multiplier) / multiplier; 
    }

    // executed before each test
    before(async () => {
        contract = await EnergyToken.at("0x5BbD383bD43aC3896B86207eFe88cf0628ad06F0");
    });

    // Test mining time of 2500 transaction calls on the EnergyToken smart contract's transfer() method 
    it("send " + numberOfTransactions + " transactions of 1 EnergyToken from account 0 to account 1", (done) => {
        // contract.Transfer(function(error, event) { 
        //     i++;
        //     console.log(event)
        //     if(i == 1)
        //         startTime = performance.now();

        //     if (i == numberOfTransactions) {
        //         finishTime = performance.now();
        //         console.log("Transactions confirmed!" + " It took " + round((finishTime - startTime)/1000,2) + " seconds to confirm " + numberOfTransactions + " transactions");
        // .       done();
        //     }
        // });

        // contract.getPastEvents('Transfer', {
        //     filter: { from: accounts[0], to: accounts[1] },
        //     fromBlock: 0,
        //     toBlock: 'latest'
        // }, function(error, result) {
        //     if(error) {
        //         console.log(error, 'error');
        //     } else {
        //         console.log(result, 'result');
        //     }
        // });

        for (let j = 0; j < numberOfTransactions; j++) {
            contract.transfer(accounts[0], 1, { from:accounts[1] });
        }
        console.log("Finished sending " + numberOfTransactions + " transactions from account 1!!" + accounts[1] + " to "  + accounts[0]);
    });

    it("Calculate average gas used by the transfer() function", async () => {
        let result = await contract.transfer(accounts[1], 1);  
        let hash = await result.tx;
        let tx = await web3.eth.getTransactionReceipt(hash);
        let gasUsed = await tx.gasUsed;
        console.log(" Gas used for a 'Transfer' transaction: " + gasUsed);
    });

    it("Calculate average gas used by the approve() function", async () => {       
        let result = await contract.approve(accounts[1], 1000);  
        let hash = await result.tx;
        let tx = await web3.eth.getTransactionReceipt(hash);
        let gasUsed = await tx.gasUsed;
        console.log(" Gas used for an 'Approve' transaction: " + gasUsed);
    }); 

    it("Calculate average gas used by the transferFrom() function", async () => {
        await contract.approve(accounts[1], 100, { from: accounts[0] });  
        let result = await contract.transferFrom(accounts[0], accounts[1], 100, { from: accounts[1] });  
        let hash = await result.tx;
        let tx = await web3.eth.getTransactionReceipt(hash);
        let gasUsed = await tx.gasUsed;
        console.log(" Gas used for an 'Approve' transaction: " + gasUsed);
    });
});

Note: My version of web3 is 1.2.6

Answer 1

I suggest you should check your web3 version again by running in the terminal npm view web3 version in the root of your project. And then again you can check the version in the javascript by doing console.log(web3.version);. If it's really 1.x.x then you should be able to filter the events like this:

contract.getPastEvents('Transfer', {
    filter: {'from': accounts[0], 'to': accounts[1]},
    fromBlock: 0,
    toBlock: 'latest'
}, function(error, result) {
    if(error) {
        console.log(error, 'error');
    } else {
        console.log(result, 'result');
    }
});

It's also not normal behavior contract.events to return null for web3 1.x.x. Here are the docs how web3 1.x.x is dealing with events. If the problem still appears post your smart contract code here so we can test.