openzeppelin-test-environment is quite a new package, it doesn't tell how to initialize the upgradeable contract

https://github.com/OpenZeppelin/openzeppelin-test-environment

Just a basic example from the link above:

const { accounts, contract } = require('@openzeppelin/test-environment');
const [ owner ] = accounts;

const { expect } = require('chai');

const MyContract = contract.fromArtifact('MyContract'); // Loads a compiled contract

describe('MyContract', function () {
  it('deployer is owner', async function () {
    const myContract = await MyContract.new({ from: owner });
    expect(await myContract.owner()).to.equal(owner);
  });
});

How to add an upgradeable contract which doesn't have constructor but initialize method?

openzeppelin-test-environment is quite a new package, it doesn't tell how to initialize the upgradeable contract in the information below:

https://github.com/OpenZeppelin/openzeppelin-test-environment

Just a basic example from the link above:

const { accounts, contract } = require('@openzeppelin/test-environment');
const [ owner ] = accounts;

const { expect } = require('chai');

const MyContract = contract.fromArtifact('MyContract'); // Loads a compiled contract

describe('MyContract', function () {
  it('deployer is owner', async function () {
    const myContract = await MyContract.new({ from: owner });
    expect(await myContract.owner()).to.equal(owner);
  });
});

How to add an upgradeable contract which doesn't have constructor but initialize method?