title: Is there a jasmine matcher to compare objects on subsets of their properties
body: <p>I have an object that may be extended along my behavior under test, but I want to make sure that the original properties are still there.</p>
  
  <pre><code>var example = {'foo':'bar', 'bar':'baz'}
  
  var result = extendingPipeline(example)
  // {'foo':'bar', 'bar':'baz', 'extension': Function}
  
  expect(result).toEqual(example) //fails miserably
  </code></pre>
  
  <p>I'd like to have a matcher that would pass in this case, along the lines of:</p>
  
  <pre><code>expect(result).toInclude(example)
  </code></pre>
  
  <p>I know that I can write a custom matcher, but it seems to me that this is such a common problem that a solution should be out there already. Where should I look for it?</p>