I'm working through the tutorial [here](http://teropa.info/blog/2015/09/10/full-stack-redux-tutorial.html) and finding that pretty much all but the first most elementary chai tests are failing for me. Here is the current example for a failing test

```
import {List, Map} from 'immutable';
import {expect} from 'chai';

import {setEntries} from '../src/core';

describe('application logic', () => {
    describe('setEntries', () => {
        it('adds the entries to the state', () => {
            const state = Map();
            const entries = List.of('Trainspotting', '28 Days Later');
            const nextState = setEntries(state, entries);
            expect(nextState).to.equal(Map({
                entries: List.of('Trainspotting', '28 Days Later')
            }));
        });
    });
});

```

and here is the code testing against:

```
import {List} from 'immutable';

export function setEntries(state, entries){
    return state.set('entries', entries);
}

```

here is the error message for the failure:

```
1) application logic setEntries adds the entries to the state:

      AssertionError: expected { Object (size, _root, ...) } to equal { Object (size, _root, ...) }
      + expected - actual

                 "size": 2
               }
             ]
           ]
      -    "ownerID": [undefined]
      +    "ownerID": {}
         }
         "size": 1
       }

```

I can't seem to find any meaningful documentation on what this error means, and don't see any other users of this tutorial mentioning similar issues. Any idea where this is choking?