expect to be rejected with a property

[piotr-s-brainhub]

it's probably a feature request but I write my environment details because maybe it's a bug

Node version: 8.6.0
npm version: 5.2.0
chai-as-promised version: 7.1.1
chai version: 4.1.2

I have the following code:

const chai = require('chai');
const chaiAsPromised = require('chai-as-promised');

chai.use(chaiAsPromised);

const expect = chai.expect;

const error = new Error;
error.foo = 123;

expect(Promise.reject(error)).to.be.rejectedWith(Error, { foo: 123 });

Actual behavior:

(node:51977) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 2): AssertionError: expected promise to be rejected with an error including { foo: 123 } but got ''
(node:51977) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

Expected behavior:

Of cource if the rejected error doesn't have the expected field or its field has another value, it should fail.

[piotr-s-brainhub]

It also doesn't work:

const chai = require('chai');
const chaiAsPromised = require('chai-as-promised');

chai.use(chaiAsPromised);

const expect = chai.expect;

const error = new Error;
error.foo = 123;

expect(Promise.reject(error)).to.be.rejectedWith(Error).and.have.property('foo', 123);

I obtain:

      throw new AssertionError(msg, {
      ^
AssertionError: expected {} to have property 'foo'

[piotr-s-brainhub]

It works when I add .eventually
so such a test succeeds:

const chai = require('chai');
const chaiAsPromised = require('chai-as-promised');

chai.use(chaiAsPromised);

const expect = chai.expect;

const error = new Error;
error.foo = 123;

expect(Promise.reject(error)).to.be.eventually.rejectedWith(Error).and.have.property('foo', 123);

Therefore IMO you should improve README because nowhere I can see .eventually.rejectedWith.

[samcodrington]

I didn't find that eventually resolved my problem with the following specs
Node version: 10.6.0
npm version: 6.1.0
chai-as-promised version: 7.1.1
chai version: 4.1.2
--posting here so there's a solution as this is a major problem
given the following test

var chaiAsPromised = require("chai-as-promised");
var chai = require("chai");
chai.use(chaiAsPromised);

var should = chai.should();
var expect = chai.expect;
var asyncFunc = async function(){
  return true;
}
it("Async function should throw error", () => {
	expect(asyncFunc()).to.be.rejected; //should fail
});

This function passes with

  ✓ Async function should throw error
(node:11142) UnhandledPromiseRejectionWarning: AssertionError: expected promise to be rejected but it was fulfilled with true
(node:11142) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:11142) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

  1 passing (12ms)

and can be fixed by using await keyword on the expect function!

it("Async function should throw error", async () => {
	await expect(asyncFunc()).to.be.rejected;
});

Now returns:

 1) Async function should throw error

  0 passing (12ms)
  1 failing

  1) Async function should throw error:
     AssertionError: expected promise to be rejected but it was fulfilled with true

Not entirely sure why this is the case, I think it might be failing due to the way .to.be.rejected() wraps the function in a Promise.

[Ceesjansen]

@piotr-s-brainhub

Hi, just tested your solution and I can confirm it works, thank you! And I agree with updating the docs :)

[piotr-s-brainhub]

@Ceesjansen

Anyway now you can use async/ await so chai-as-promised is no longer needed.

[unicornist]

this works too:

expect(Promise.reject).to.be.rejectedWith(Error).eventually.with.property('name', 'YourError')

[sebastianst]

The docs are still not updated on this, please update. I had to find this issue to know that adding eventually is necessary. Btw a slightly shorter version works too

expect(Promise.reject).to.be.eventually.rejected.with.property('foo', 'bar');