Lottery.test.js

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

const {interface, bytecode } = require('../compile');

let lottery;
let accounts;

beforeEach(async () => {
    accounts = await web3.eth.getAccounts();

    lottery = await new web3.eth.Contract(JSON.parse(interface))
    .deploy({data: bytecode}).send({from: accounts[0], gas: '1000000'});
});

describe('Lottery contract',()=>{
    it('Deploys a contracts ',()=>{
        assert.ok(lottery.options.address);
    });
    it('allows one account to enter ',async ()=>{
        await lottery.methods.enter().send({
            from:accounts[0],
            value: web3.utils.toWei('0.02','ether')
        });
        const players = await lottery.methods.getPlayers().call({
            from: accounts[0]
        });

        assert.equal(accounts[0], players[0]);
        assert.equal(1,players.length);
    });
    it('allows multiple account to enter ',async ()=>{
        await lottery.methods.enter().send({
            from:accounts[0],
            value: web3.utils.toWei('0.02','ether')
        });
        await lottery.methods.enter().send({
            from:accounts[1],
            value: web3.utils.toWei('0.02','ether')
        });
        await lottery.methods.enter().send({
            from:accounts[2],
            value: web3.utils.toWei('0.02','ether')
        });
        const players = await lottery.methods.getPlayers().call({
            from: accounts[0]
        });

        assert.equal(accounts[0], players[0]);
        assert.equal(accounts[1], players[1]);
        assert.equal(accounts[2], players[2]);
        assert.equal(3,players.length);
    });
    it('Requires minimum amount of ether to enter ',async()=>{
        try{
            await lottery.methods.enter().send(
                {
                    from:accounts[0],
                    value: 0
                }
            );
            //if execution comes here it means it does not throw error.
            //  So assert(false) will fail the test.
            assert(false);
        }catch(err)
        {
            // here if execution comes it means that error occured and test is passed.
            assert(err);
        }
    });
    it('Only manager can pick winner ',async()=>{
        try{
            await lottery.methods.pickWinner().send(
                {
                    from:accounts[1],
                    value: 0
                }
            );
            //if execution comes here it means it does not throw error.
            //  So assert(false) will fail the test.
            assert(false);
        }catch(err)
        {
            // here if execution comes it means that error occured and test is passed.
            assert(err);
        }
    });

    it('sends money to the winner and resets the players array',async()=>{
        await lottery.methods.enter().send({
            from:accounts[0],
            value:web3.utils.toWei('2','ether')
        });

        const initialBalance = await web3.eth.getBalance(accounts[0]);
        await lottery.methods.pickWinner().send({
            from:accounts[0]
        });
        const finalBalance = await web3.eth.getBalance(accounts[0]);
        const difference = finalBalance-initialBalance;
        assert(difference > web3.utils.toWei('1.8'));
    });
});