title: getting the object passed as an argument to a stubbed method with Mocha
body: <pre><code>Foo.expects(:bar)
  Foo.bar(:abc =&gt; 123, :xyz =&gt; 987)
  
  # assert Foo.bar was called with a hash that has a key of :abc == 123
  </code></pre>
  
  <p>Basically I want to examine the object passed as an argument to a stubbed method, in order to inspect on a value of that object.  In my situation I can't use <code>Foo.expects(:bar).with({:abc =&gt; 123})</code> because I know the object wont equal each other.  I just want to compare a sub-value of the argument.</p>
  
  <p>Surely this is possible, I just can't find the syntax or strategy here.</p>