title: rspec to test whether ruby method returns an array
body: <p>I have a method which returns an array. I need to test it using rspec. Is there any method with which we can test like:</p>
  
  <pre><code>def get_ids
    ####returns array of ids
  end
  
  subject.get_ids.should be_array
  </code></pre>
  
  <p>or</p>
  
  <pre><code>result = subject.get_ids
  result.should be an_instance_of(Array)
  </code></pre>