title: Problems casting a null object with Spock
body: <p>I have a Spock test that fails over two Mac OS X Lion machines, but works over other Linux machines and the <a href="http://meetspock.appspot.com/" rel="nofollow noreferrer">Spock Web Console</a>.</p>
  
  <p>I found another related question: <a href="https://stackoverflow.com/q/10040162/462015">Why I get a cannot cast object 'null' error, when testing my controller?</a></p>
  
  <p>I'm using Grails 2.0.0 and Spock 0.6. Any suggestions? Seems to be a bug</p>
  
  <pre><code>def "casting null object"() {
      expect:
      null as BigDecimal == null
  }
  
  | Failure:  casting null object(com.arturoherrero.MySpec)
  |  org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast object 'null' with class 'org.codehaus.groovy.runtime.NullObject' to class 'java.math.BigDecimal'
  </code></pre>