title: Jest Received: serializes to the same string on Object
body: <p>newbie testing here and I ran into this error</p>
  
  <p><strong>module.js</strong></p>
  
  <pre><code>import reducer from './reducer';
  
  export default function getGModalModule({ domain }) {
    return {
      id: `GModal-module-${domain}`,
      reducerMap: {
        [domain]: reducer({
          domain,
        }),
      },
    };
  }
  
  </code></pre>
  
  <p><strong>module.test.js</strong></p>
  
  <pre><code>import getGModalModule from '../module';
  import reducer from '../reducer';
  
  describe('getGModalModule', () =&gt; {
    it('returns the correct module', () =&gt; {
      const reducers = reducer({
        domain: 'demo'
      })
  
      const expectVal = getGModalModule({
        domain: 'demo'
      });
      const received = {
        id: `GModal-module-demo`,
        reducerMap: {
          demo: reducers,
        },
      }
      console.log("expectVal", expectVal)
      console.log("received", received)
  
      expect(expectVal).toEqual(received);
    });
  });
  </code></pre>
  
  <p>The error says something like this:</p>
  
  <pre><code>Expected: {"id": "GModal-module-demo", "reducerMap": {"demo": [Function gModalReducer]}}
  Received: serializes to the same string
  </code></pre>
  
  <p>I've tried to log out the result and they look exactly the same, any idea why this doesn't pass the test ?</p>
  
  <pre><code>expectVal { id: 'GModal-module-demo', reducerMap: { demo: [Function: gModalReducer] } }
  received { id: 'GModal-module-demo', reducerMap: { demo: [Function: gModalReducer] } }
  </code></pre>
  
  <p>Thanks in advance,</p>