inbox.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 accounts;
let inbox;
beforeEach(async () => {
  accounts = await web3.eth.getAccounts();
  inbox= await new web3.eth.Contract(JSON.parse(interface))
    .deploy({ data: bytecode, arguments: ['Hi there!']})
    .send({from : accounts[0], gas: '1000000'})
});


describe('Inbox', () => {
  it('deploy a contract', () => {
    assert.ok(inbox.options.address);
  });
  it('has a default message', async () => {
    const message=await inbox.methods.message().call();
    assert.equal(message,"Hi there!");
  });
  it('can change the message', async () => {
    await inbox.methods.setMessage('bye').send({ from: accounts[0] })
    const message=await inbox.methods.message().call();
    assert.equal(message,'bye');
  });
});