isEqual() on iterable ignores other properties

[jheeffer]

🐛 Bug Report

Testing iterable objects with isEqual() ignores other properties on the iterable

To Reproduce

let next = () => ({ value: undefined, done: true });
test('iterable', () => {
    expect({ 
        [Symbol.iterator]: () => ({ next }), 
        data: ['foo'] 
    }).toEqual({ 
        [Symbol.iterator]: () => ({ next }), 
        data: [] 
    })
});

Same behaviour when using the iterator of data property:

let data = ['foo'], data2 = [];
test('foo', () => {
    expect({ 
        [Symbol.iterator]: data[Symbol.iterator], 
        data
    }).toEqual({ 
        [Symbol.iterator]: data2[Symbol.iterator], 
        data: data2
    })
});

both result in

PASS  test/foo.test.js
  ✓ foo (6ms)

Expected behavior

Other properties are evaluated when object is iterable. Like when removing the iterators from above code:

 FAIL  test/foo.test.js
  ✕ foo (14ms)

  ● foo

    expect(received).toEqual(expected)

    Difference:

    - Expected
    + Received

      Object {
    -   "data": Array [],
    +   "data": Array [
    +     "foo",
    +   ],
      }

Link to repl or repo (highly encouraged)

https://repl.it/repls/CaringPrimarySupport

Run npx envinfo --preset jest

Paste the results here:

npx: installed 1 in 1.537s

  System:
    OS: Linux 4.4 Ubuntu 16.04.1 LTS (Xenial Xerus)
    CPU: (8) x64 Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz
  Binaries:
    Node: 8.9.1 - /usr/bin/node
    npm: 6.4.1 - /usr/bin/npm
  npmPackages:
    jest: ^24.7.1 => 24.7.1

[jeysal]

This reproduces for me, and it's a bug with our custom iterableEquality. With Arrays, it works.

[d7my11]

I'll send a PR

[SimenB]

https://github.com/facebook/jest/releases/tag/v28.0.0-alpha.5

[github-actions]

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