old_contents: #!/usr/bin/env python
  
  import cleanup_marathon_orphaned_images
  
  
  # These should be left running
  mesos_deployed_old = {
      'Names': ['/mesos-deployed-old', ],
  }
  mesos_undeployed_young = {
      'Names': ['/mesos-undeployed-young', ],
  }
  nonmesos_undeployed_old = {
      'Names': ['/nonmesos-undeployed-old', ],
  }
  # These should be cleaned up
  mesos_undeployed_old = {
      'Names': ['/mesos-undeployed-old', ],
  }
  running_images = [
      mesos_deployed_old,
      nonmesos_undeployed_old,
      mesos_undeployed_young,
      mesos_undeployed_old,
  ]
  
  
  def test_get_mesos_images():
      actual = cleanup_marathon_orphaned_images.get_mesos_images(running_images)
      assert nonmesos_undeployed_old not in actual
  
  
  def test_get_old_images():
      pass
  
new_contents: #!/usr/bin/env python
  
  import cleanup_marathon_orphaned_images
  
  
  # These should be left running
  mesos_deployed_old = {
      'Names': ['/mesos-deployed-old', ],
  }
  mesos_undeployed_young = {
      'Names': ['/mesos-undeployed-young', ],
  }
  nonmesos_undeployed_old = {
      'Names': ['/nonmesos-undeployed-old', ],
  }
  # These should be cleaned up
  mesos_undeployed_old = {
      'Names': ['/mesos-undeployed-old', ],
  }
  running_images = [
      mesos_deployed_old,
      nonmesos_undeployed_old,
      mesos_undeployed_young,
      mesos_undeployed_old,
  ]
  
  
  def test_get_mesos_images():
      assert nonmesos_undeployed_old in running_images
      actual = cleanup_marathon_orphaned_images.get_mesos_images(running_images)
      assert nonmesos_undeployed_old not in actual
  
  
  def test_get_old_images():
      pass
  
subject: Clarify intent and fail fast