is called on empty stack", {
  given "an empty stack",{
    stack = new Stack()
  }

  when "pop is called", {
    popnull = {
      stack.pop()
    }
  }

  then "an exception should be thrown", {
    ensureThrows(RuntimeException){
      popnull()
    }
  }
  
  and "then the stack should still be empty", {
      stack.empty.shouldBe true
    }

}
</code></pre>

<p>Does it not convey the intention clearly? Of course it does!! It's so easy too.</p>
<p>Take notice of multiple <code>