anchor.diff:  
   [source,groovy]
   ----
  -def anySubscriber = GroovySpy(RealSubscriber, global: true)
  +RealSubscriber anySubscriber = GroovySpy(global: true)
   
   1 * new RealSubscriber("Fred")
   ----
  
positive.code: [[DetectingMockObjects]]
  === Detecting Mock Objects
  
  To find out whether a particular object is a Spock mock object, use a `org.spockframework.mock.MockDetector`:
  
  [source,groovy]
  ----
  def detector = new MockDetector()
  def list1 = []
  def list2 = Mock(List)
  
  expect:
  !detector.isMock(list1)
  detector.isMock(list2)
  ----
  
  A detector can also be used to get more information about a mock object:
  
  [source,groovy]
  ----
  def mock = detector.asMock(list2)
  
  expect:
  mock.name == "list2"
  
negative.code: 
  [source,groovy]
  ----
  Subscriber subscriber = Mock {
     1 * receive("hello")
     1 * receive("goodbye")
  }
  