text: from django.contrib.auth import get_user_model
  from django.urls import reverse
  from django.test import TestCase
  
  from rest_framework import status
  from rest_framework.test import APIClient
  
  from core.models import Tag
  
  from recipe.serializers import TagSerializer
  
  
  TAGS_URL = reverse('recipe:tag-list')
  
  
  class PublicTagsApiTests(TestCase):
      """Test the publicly available tags API"""
  
      def setUp(self):
          self.client = APIClient()
  
      def test_login_required(self):
          """Test that login is required for retrieving tags"""
          res = self.client.get(TAGS_URL)
  
          self.assertEqual(res.status_code, status.HTTP_401_UNAUTHORIZED)
  
  
  class PrivateTagsApiTests(TestCase):
      """Test the authorized user tags API"""
  
      def setUp(self):
          self.user = get_user_model().objects.create_user(
              'test@xxx.com',
              'password123'
          )
          self.client = APIClient()
          self.client.force_authenticate(self.user)
  
      def test_retrieve_tags(self):
          """Test retrieve tags"""
          Tag.objects.create(user=self.user, name='Vegan')
          Tag.objects.create(user=self.user, name='Dessert')
  
          res = self.client.get(TAGS_URL)
  
          tags = Tag.objects.all().order_by('-name')
          serializer = TagSerializer(tags, many=True)
  
          self.assertEqual(res.status_code, status.HTTP_200_OK)
          self.assertEqual(res.data, serializer.data)
  
      def test_tags_limited_to_user(self):
          """Test that tags returned are for authenticated user"""
          user2 = get_user_model().objects.create_user(
              'other@xxx.com',
              'testpass'
          )
          Tag.objects.create(user=user2, name='Fruity')
          tag = Tag.objects.create(user=self.user, name='Comfort food')
  
          res = self.client.get(TAGS_URL)
  
          self.assertEqual(res.status_code, status.HTTP_200_OK)
          self.assertEqual(len(res.data), 1)
          self.assertEqual(res.data[0]['name'], tag.name)
  
      def test_create_tag_successful(self):
          """Test creating a new tag"""
          payload = {'name': 'Test tag'}
          self.client.post(TAGS_URL, payload)
  
          exists = Tag.objects.filter(
              user=self.user,
              name=payload['name']
          ).exists()
          self.assertTrue(exists)
  
      def test_create_tag_invalid(self):
          """Test creating a new tag with invalid payload"""
          payload = {'name': ''}
          res = self.client.post(TAGS_URL, payload)
  
          self.assertEqual(res.status_code, status.HTTP_400_BAD_REQUEST)
  