old_contents: import datetime
  import pytest
  
  from components.merchandise.music.models import Album, Single
  from components.merchandise.music.factories import (AlbumFactory,
      BaseFactory, SingleFactory)
  from components.people.factories import GroupFactory
  
  
  pytestmark = pytest.mark.django_db
  
  def test_album_factory():
      factory = AlbumFactory()
      assert isinstance(factory, Album)
      assert 'album' in factory.romanized_name
      assert factory.identifier == 'album'
  
  
  def test_album_get_absolute_url(client):
      factory = AlbumFactory()
      response = client.get(factory.get_absolute_url())
      assert response.status_code == 200
  
  
  def test_single_factory():
      factory = SingleFactory()
      assert isinstance(factory, Single)
      assert 'single' in factory.romanized_name
      assert factory.identifier == 'single'
  
  
  def test_single_get_absolute_url(client):
      factory = SingleFactory()
      response = client.get(factory.get_absolute_url())
      assert response.status_code == 200
  
  
  def test_single_get_previous_and_next():
      single1 = SingleFactory(number='1', romanized_name='single1', released=datetime.date.today() - datetime.timedelta(days=14))
      single2 = SingleFactory(number='2', romanized_name='single2', released=datetime.date.today() - datetime.timedelta(days=7))
  
      group = GroupFactory()
      single1.groups.add(group)
      assert single1.groups.exists()
      single2.groups.add(group)
      assert single2.groups.exists()
  
      previous = single2.get_previous
      assert previous == single1
  
      next = single1.get_next
      assert next == single2
  
new_contents: import datetime
  import pytest
  
  from components.merchandise.music.models import Album, Single
  from components.merchandise.music.factories import (AlbumFactory,
      BaseFactory, SingleFactory)
  from components.people.factories import GroupFactory
  
  
  pytestmark = pytest.mark.django_db
  
  def test_album_factory():
      factory = AlbumFactory()
      assert isinstance(factory, Album)
      assert 'album' in factory.romanized_name
      assert factory.identifier == 'album'
  
  
  def test_album_get_absolute_url(client):
      factory = AlbumFactory()
      response = client.get(factory.get_absolute_url())
      assert response.status_code == 200
  
  
  def test_single_factory():
      factory = SingleFactory()
      assert isinstance(factory, Single)
      assert 'single' in factory.romanized_name
      assert factory.identifier == 'single'
  
  
  def test_single_get_absolute_url(client):
      factory = SingleFactory()
      response = client.get(factory.get_absolute_url())
      assert response.status_code == 200
  
  
  def test_single_get_previous_and_next():
      single1 = SingleFactory(romanized_name='single1', released=datetime.date.today() - datetime.timedelta(days=14), number='1')
      single2 = SingleFactory(romanized_name='single2', released=datetime.date.today() - datetime.timedelta(days=7), number='2')
      single3 = SingleFactory(romanized_name='single2', released=datetime.date.today())
  
      group = GroupFactory()
      single1.groups.add(group)
      assert single1.groups.exists()
      single2.groups.add(group)
      assert single2.groups.exists()
      single3.groups.add(group)
      assert single2.groups.exists()
  
      assert single1.get_next == single2
      assert single2.get_previous == single1
      assert single2.get_next != single3
  
subject: Add a failing case to the new get_previous/_next test.