Getting hold of web3 from inside a Truffle JS test

Question

How do I access a web3 instance from inside a Truffle Javascript test?

Answer 1

It turns out that Truffle automatically injects web3 into the Javascript test file. Simply use it directly as follows:

//  test/mycontract.js

...

contract("MyContract", accounts => {
  var accountA = accounts[0];

  it("...should...", async () => {

    const accountABalance = await web3.eth.getBalance(accountA);

    ...
  });
});

Answer 2

At the top of your truffle .js file you can write:

const Web3 = require('web3');
const web3 = new Web3(new Web3.providers.HttpProvider('http://localhost:9545'));

And in one of your it test blocks, you can then use web3.[desired func].