Unit test ImmutableJs collections using newState.equals(expectState) not expect(newState).toEqual(expectState)

reducer.tests.js

import expect from 'expect';
import whynotEqual from 'is-equal/why';

import appLayoutReducer from '../reducer';
import {
    hideLeftMenuIcon,
    showLeftMenuIcon,
} from '../actions';
import { fromJS } from 'immutable';

describe('appLayoutReducer', () => {
  let state;
  beforeEach(() => {
    state = fromJS({
      showLeftMenuIcon: false,
    });
  });

  it('should return the initial state', () => {
    const expectedResult = state;
    expect(appLayoutReducer(undefined, {})).toEqual(expectedResult);
  });

  it('should handle the showLeftMenuIcon action correctly', () => {
    const expectedResult = state
      .set('showLeftMenuIcon', true);

    expect(appLayoutReducer(state, showLeftMenuIcon())).toEqual(expectedResult);
  });

  it('should handle the hideLeftMenuIcon action correctly', () => {
    const initState = state
      .set('showLeftMenuIcon', true);

    const expectedResult = state
      .set('showLeftMenuIcon', false);

    const newState = appLayoutReducer(initState, hideLeftMenuIcon());

    expect(newState).toEqual(expectedResult, whynotEqual(newState, expectedResult));
    expect(newState.equals(expectedResult)).toEqual(true);
  });
});

Notice in the last test, that the test in line 40 fails, but line 41 works. The failure from line 40 is described by whyNotEqual() as:

FAILED TESTS:
  appLayoutReducer
    × should handle the hideLeftMenuIcon action correctly
      PhantomJS 2.1.1 (Windows 8 0.0.0)
      PhantomJS 2.1.1 (Windows 8 0.0.0)
    value at key "_root" differs: value at key "ownerID" differs: undefined !== [object Object]
    assert@webpack:///~/expect/lib/assert.js:29:0 <- test-bundler.js:34515:27
    toEqual@webpack:///~/expect/lib/Expectation.js:81:0 <- test-bundler.js:59032:30
    webpack:///app/containers/AppLayout/tests/reducer.tests.js:40:29 <- test-bundler.js:104182:69