title: How to show longer traces in Rails TestCases
body: <p>Is there a config variable to set, or some other way to get Rails <code>ActiveSupport::TestCase</code> to show <strong>more than one</strong> trace line? It is really hard to debug otherwise.</p>
  
  <p>Example:</p>
  
  <pre><code>ERROR test_something (0.73s) 
        SystemStackError: stack level too deep
        /Users/mario/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.0.9/lib/active_record/connection_adapters/abstract/database_statements.rb:153
  </code></pre>