text: from django.test import TestCase
  from django.contrib.auth import get_user_model
  from django.urls import reverse
  
  from rest_framework.test import APIClient
  from rest_framework import status
  
  
  CREATE_USER_URL = reverse("user:create")
  TOKEN_URL = reverse("user:token")
  ME_URL = reverse("user:me")
  
  
  def create_user(**params):
      """Helper function to create new user"""
      return get_user_model().objects.create_user(**params)
  
  
  class PublicUserApiTests(TestCase):
      """Test the users API (public)"""
  
      def setUp(self):
          self.client = APIClient()
  
      def test_create_valid_user_success(self):
          """Test creating using with a valid payload is successful"""
          payload = {
              "email": "test@londonappdev.com",
              "password": "testpass",
              "name": "name",
          }
          res = self.client.post(CREATE_USER_URL, payload)
  
          self.assertEqual(res.status_code, status.HTTP_201_CREATED)
          user = get_user_model().objects.get(**res.data)
          self.assertTrue(user.check_password(payload["password"]))
          self.assertNotIn("password", res.data)
  
      def test_user_exists(self):
          """Test creating a user that already exists fails"""
          payload = {"email": "test@londonappdev.com", "password": "testpass"}
          create_user(**payload)
          res = self.client.post(CREATE_USER_URL, payload)
  
          self.assertEqual(res.status_code, status.HTTP_400_BAD_REQUEST)
  
      def test_password_too_short(self):
          """Test that password must be more than 5 characters"""
          payload = {"email": "test@londonappdev.com", "password": "pw", "name": "Mar"}
          res = self.client.post(CREATE_USER_URL, payload)
  
          self.assertEqual(res.status_code, status.HTTP_400_BAD_REQUEST)
          user_exists = get_user_model().objects.filter(email=payload["email"]).exists()
          self.assertFalse(user_exists)
  
      def test_create_token_for_user(self):
          """Test that a token is created for the user"""
          payload = {"email": "test@londonappdev.com", "password": "testpass"}
          create_user(**payload)
          res = self.client.post(TOKEN_URL, payload)
  
          self.assertIn("token", res.data)
          self.assertEqual(res.status_code, status.HTTP_200_OK)
  
      def test_create_token_invalid_credentials(self):
          """Test that token is not created if invalid credentials are given"""
          create_user(email="test@londonappdev.com", password="testpass")
          payload = {"email": "test@londonappdev.com", "password": "wrong"}
          res = self.client.post(TOKEN_URL, payload)
  
          self.assertNotIn("token", res.data)
          self.assertEqual(res.status_code, status.HTTP_400_BAD_REQUEST)
  
      def test_create_token_no_user(self):
          """Test that token is not created if user doens't exist"""
          payload = {"email": "test@londonappdev.com", "password": "testpass"}
          res = self.client.post(TOKEN_URL, payload)
  
          self.assertNotIn("token", res.data)
          self.assertEqual(res.status_code, status.HTTP_400_BAD_REQUEST)
  
      def test_create_token_missing_field(self):
          """Test that email and password are required"""
          res = self.client.post(TOKEN_URL, {"email": "one", "password": ""})
          self.assertNotIn("token", res.data)
          self.assertEqual(res.status_code, status.HTTP_400_BAD_REQUEST)
  
      def test_retrieve_user_unauthorized(self):
          """Tests that authentication is required"""
          res = self.client.get(ME_URL)
          self.assertEqual(res.status_code, status.HTTP_401_UNAUTHORIZED)
  
  
  class PrivateUserApiTests(TestCase):
      """Test API requests that require auth"""
  
      def setUp(self):
          self.user = create_user(
              email="test@londonappdev.com", password="pw", name="Mar"
          )
          self.client = APIClient()
          self.client.force_authenticate(user=self.user)
  
      def test_retrieve_profile_success(self):
          """Test retrieving profile for logged in user"""
          res = self.client.get(ME_URL)
          self.assertEqual(res.status_code, status.HTTP_200_OK)
          self.assertEqual(res.data, {"name": self.user.name, "email": self.user.email})
  
      def test_post_me_not_allowed(self):
          """Test that post is not allowed under any url"""
          res = self.client.post(ME_URL, {})
          self.assertEqual(res.status_code, status.HTTP_405_METHOD_NOT_ALLOWED)
  
      def test_update_user_profile(self):
          """Test updating user profile for authenticated user"""
          payload = {"name": "new name", "password": "newpass"}
          res = self.client.patch(ME_URL, payload)
  
          self.user.refresh_from_db()
          self.assertEqual(self.user.name, payload["name"])
          self.assertTrue(self.user.check_password(payload["password"]))
          self.assertEqual(res.status_code, status.HTTP_200_OK)
  