Thenable Sinon Stubs

example-usage.js

'use strict';

const expect = require('chai').expect;
const stubAsPromised = require('./stub-as-promised');
const lib = {
  method: () => {}
};
let sinon;

describe('a test', () => {
  let myStub;

  beforeEach(() => {
    setTimeout(() => {
      lib.method();
    }, 1000);
  });

  beforeEach(() => {
    sinon = require('sinon').sandbox.create();
    myStub = stubAsPromised(sinon, lib, 'method');
  });

  afterEach(() => {
    sinon.restore();
  });

  it('does not get called until after myStub.promise resolves', () => {
    return lib.method.promise.then(() => {
      expect(lib.method.called).to.equal(true);
      expect(lib.method.args[0][0]).to.equal(undefined);
    });
  });
});

stub-as-promised.js

'use strict';

/**
 * Wrap a sinon stub in a function which resolves a promise when the stub is called.
 */
module.exports = (sandbox, object, methodName, func) => {
  let wrapper;
  func = func || function () {};

  const promise = new Promise(resolve => {
    wrapper = () => {
      resolve();
      return func.apply(null, arguments);
    };
  });

  const stub = sandbox.stub(object, methodName, wrapper);
  stub.promise = promise;
  return stub;
};