Expect tests don't work with the ES6 / ES2015 Set object

Question

Issue

The test below should fail, but it is passing:

it('should fail', () => {
  const actual = new Set('a');
  const expected = new Set('b');
  expect(actual).toEqual(expected);
});

Background & Question

I'm using the expect package from npm. I'm using Babel 5 to use Set. I'm using Node 5, so the Set being used should be native. Am I doing something wrong, or does this look like a bug in the expect package in the way it handles Sets? I've cross posted an issue on the package as I'm not sure.

You could try hapijs [code](https://github.com/hapijs/code) instead of expect for assertions, I just tested the assertion and it worked — simon-p-r, Nov 23 '15 at 22:39
See this question http://stackoverflow.com/questions/31128855/comparing-ecma6-sets-for-equality — frkk, Nov 23 '15 at 22:44

score 2 · Answer 1 · edited May 23 '17 at 11:52

1. This is "expected behavior"

expect depends on deep-equal, which does not support sets and maps.

This in consistent with the behavior of node's assert :

var a = new Set('a');
var b = new Set('b');
console.log(require('assert').deepEqual(a, b) || 'ok');
// Prints 'ok' !

This issue has been discussed here :

assert: add support for Set and Map

This comment is particularly interesting :

I don't think we should do this (or anything else in #2309). Assert should remain used only for testing io.js itself, and not try to be a good general assertion library. If io.js tests need this ability enough times that we need to factor it out, we should, but until then, just adding it because it'd be nice isn't a good idea IMO.

2. Workaround

You can either:

use assert6
or (re)open the tickets to raise concern about this
or use another library, like code that @simon-p-r mentioned
or do the comparison manually. See Comparing ECMA6 sets for equality

Expect tests don't work with the ES6 / ES2015 Set object

Issue

Background & Question

1 Answers1

1. This is "expected behavior"

2. Workaround