old_contents: from unittest import TestCase
  from docker import Client
  from plum import Service
  
  
  class ServiceTestCase(TestCase):
      def setUp(self):
          self.client = Client('http://127.0.0.1:4243')
          self.client.pull('ubuntu')
  
          for c in self.client.containers():
              self.client.kill(c['Id'])
  
          self.service = Service(
              client=self.client,
              image="ubuntu",
              command=["/bin/sleep", "300"],
          )
  
      def test_up_scale_down(self):
          self.assertEqual(len(self.service.containers), 0)
  
          self.service.start()
          self.assertEqual(len(self.service.containers), 1)
  
          self.service.start()
          self.assertEqual(len(self.service.containers), 1)
  
          self.service.scale(2)
          self.assertEqual(len(self.service.containers), 2)
  
          self.service.scale(1)
          self.assertEqual(len(self.service.containers), 1)
  
          self.service.stop()
          self.assertEqual(len(self.service.containers), 0)
  
          self.service.stop()
          self.assertEqual(len(self.service.containers), 0)
  
new_contents: from unittest import TestCase
  from docker import Client
  from plum import Service
  
  
  class ServiceTestCase(TestCase):
      def setUp(self):
          self.client = Client('http://127.0.0.1:4243')
          self.client.pull('ubuntu')
  
          for c in self.client.containers(all=True):
              self.client.kill(c['Id'])
              self.client.remove_container(c['Id'])
  
          self.service = Service(
              client=self.client,
              image="ubuntu",
              command=["/bin/sleep", "300"],
          )
  
      def test_up_scale_down(self):
          self.assertEqual(len(self.service.containers), 0)
  
          self.service.start()
          self.assertEqual(len(self.service.containers), 1)
  
          self.service.start()
          self.assertEqual(len(self.service.containers), 1)
  
          self.service.scale(2)
          self.assertEqual(len(self.service.containers), 2)
  
          self.service.scale(1)
          self.assertEqual(len(self.service.containers), 1)
  
          self.service.stop()
          self.assertEqual(len(self.service.containers), 0)
  
          self.service.stop()
          self.assertEqual(len(self.service.containers), 0)
  
subject: Delete all containers on the Docker daemon before running test