old_contents: # -*- coding: utf-8 -*- 
  from stations.models import *
  from django.test import TestCase
  from datetime import datetime
  import pytz
  
  class TestProducts(TestCase):
  	fixtures = [ 'initial_data.yaml', '*']
  	
  	def setUp(self):
  		self.device = Device.objects.filter(product__name = 'CMP 11')[0]
  
  	def test_serialization(self):
  		# check if the __str__ method is defined to return the object serial_number and a device product name.
  		self.assertEquals(str(self.device), self.device.serial_number + " (" + self.device.product.name + ")")
new_contents: # -*- coding: utf-8 -*- 
  from stations.models import *
  from django.test import TestCase
  from datetime import datetime
  import pytz
  
  class TestDevices(TestCase):
  	fixtures = [ 'initial_data.yaml', '*']
  	
  	def setUp(self):
  		self.device = Device.objects.filter(product__name = 'CMP 11')[0]
  
  	def test_serialization(self):
  		# check if the __str__ method is defined to return the object serial_number and a device product name.
  		self.assertEquals(str(self.device), self.device.serial_number + " (" + str(self.device.product) + ")")
subject: Correct the name of the devices' test case to TestDevices (copy&paste bug).