I’m trying to create a test and getting the error “PromiseRejectionHandledWarning: Promise rejection was handled asynchronously”

import { Vpc } from '@pulumi/awsx/ec2';
import { describe, it } from 'mocha';

describe('Network', () => {
  const myvpc: Vpc = new Vpc('test', {
    cidrBlock: '10.0.0.0/16',
  });

  it('should use correct cidr address', (done) => {
    myvpc.vpc.cidrBlock.apply(vpc => {
      done();
    });
  });
});

full error is

Network
(node:84386) PromiseRejectionHandledWarning: Promise rejection was handled asynchronously (rejection id: 3)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:84386) PromiseRejectionHandledWarning: Promise rejection was handled asynchronously (rejection id: 4)

Does anybody know what is happening here?