title: unittesting sqlalchemy BinaryExpressions
body: <p>I'm writing some unittests for some code that uses SQLAlchemy. I want to test <code>filter</code> calls, but it seems that SQLAlchemy <code>BinaryExpression</code> objects created with the same arguments don't compare equal:</p>
  
  <pre><code>AssertionError: Expected call: filter(&lt;sqlalchemy.sql.elements.BinaryExpression object at 0x1037607d0&gt;)
  Actual call: filter(&lt;sqlalchemy.sql.elements.BinaryExpression object at 0x1037590d0&gt;)
  </code></pre>
  
  <p>I suppose I can cast them both to strings and compare those, but that seems hacky, and I'd really rather not be forced to try to debug string comparisons if I don't have to. Are there any better/more-structured ways to compare <code>BinaryExpression</code>s in unittests?</p>