text: import pytest
  from os import remove
  from model import User, Car, InvalidPassword, database_proxy, Location
  from peewee import SqliteDatabase, DoesNotExist, IntegrityError
  
  try:
      remove('data/test.db')
  except FileNotFoundError:
      pass
  
  database = SqliteDatabase('data/test.db')
  database_proxy.initialize(database)
  
  with database:
      database.create_tables([User, Car])
  
  
  user1 = User.signup(
      username='user1',
      password='password1'
  )
  
  user2 = User.signup(
      username='user2',
      password='password2'
  )
  
  user3 = User.signup(
      username='user3',
      password='password3'
  )
  
  
  car1 = Car.create(user=user1, license_plate='LOL1337',
                    latitude=19.341803, longitude=-99.196494)
  car2 = Car.create(user=user1, license_plate='ASAP123',
                    latitude=19.341803, longitude=-99.196494)
  car3 = Car.create(user=user1, license_plate="FTW6667",
                    latitude=19.520504, longitude=-99.109185)
  
  
  @pytest.fixture()
  def default_user():
      return user1
  
  
  @pytest.fixture()
  def empty_user():
      return user2
  
  
  @pytest.fixture()
  def mutable_user():
      return user3
  
  
  @pytest.fixture()
  def default_user_cars():
      return [car1, car2, car3]
  
  
  @pytest.fixture()
  def default_car():
      return car1
  
  
  @pytest.fixture()
  def default_location():
      return Location(19.341803, 99.196494)
  
  
  class TestLocation:
      def test_create(self):
          loc = Location.create_from_string('19.456233', '-99.109234')
          assert loc.latitude == 19.456233
          assert loc.longitude == -99.109234
  
      def test_incorrect_format(self):
          with pytest.raises(ValueError):
              Location.create_from_string('Hello', 'World')
  
      def test_incorrect_latitude(self):
          with pytest.raises(ValueError):
              Location.create_from_string('-102.345234', '-99.134938')
  
      def test_incorrect_longitude(self):
          with pytest.raises(ValueError):
              Location.create_from_string('-32.345234', '-209.134938')
  
      def test_iterable(self, default_location):
          expected_list = [default_location.latitude, default_location.longitude]
          assert expected_list == [c for c in default_location]
  
  
  class TestUsers:
      def test_signup(self):
          new_user = User.signup('user_new', 'password_new')
          assert new_user.id is not None
          User.authenticate('user_new', 'password_new')
          expected_user = User.get(User.username == 'user_new')
          assert expected_user.id == new_user.id
  
      def test_auth_valid(self):
          # Must not raise an exception
          User.authenticate('user2', 'password2')
  
      def test_auth_invalid_user(self):
          with pytest.raises(DoesNotExist):
              User.authenticate('user4', 'password2')
  
      def test_auth_invalid_password(self):
          with pytest.raises(InvalidPassword):
              User.authenticate('user1', 'badpassword')
  
  
  class TestCars:
      def test_create(self, mutable_user, default_location):
          car = Car.create_with_user(mutable_user, 'TEST123', default_location)
          assert car.id is not None
  
      def test_create_invalid_plates(self, default_user, default_location):
          with pytest.raises(ValueError):
              Car.create_with_user(default_user, '     ', default_location)
  
      def test_create_duplicate_plates(self, default_user, default_car,
                                       default_location):
          with pytest.raises(IntegrityError):
              Car.create_with_user(default_user, default_car.license_plate,
                                   default_location)
  
      def test_find_cars_by_user(self, default_user, default_user_cars):
          found_ids = set(car.id for car in Car.find_user_cars(default_user))
          assert set(car.id for car in default_user_cars) == found_ids
  
      def test_find_empty_car_list(self, empty_user):
          assert len(Car.find_user_cars(empty_user)) == 0
  
      def test_find_car_by_plate(self, default_user, default_car):
          found_car = Car.find_car_by_plate(default_user,
                                            default_car.license_plate)
          assert found_car.id == default_car.id
  
      def test_car_not_found_for_user(self, default_user, empty_user,
                                      default_car):
          with pytest.raises(DoesNotExist):
              Car.find_car_by_plate(empty_user, default_car.license_plate)
  
          with pytest.raises(DoesNotExist):
              Car.find_car_by_plate(default_user, 'MADEUP999')
  
      def test_update_location(self, default_car, default_location):
          assert tuple(default_car.location()) != tuple(default_location)
  
          default_car.update_location(default_location)
          updated_car = Car.get_by_id(default_car.id)
          assert tuple(updated_car.location()) == tuple(default_location)
  
      def test_delete_car(self, mutable_user):
          car = Car.find_car_by_plate(mutable_user, 'TEST123')
          num_deleted = car.delete_instance()
          assert num_deleted == 1
          assert len(Car.find_user_cars(mutable_user)) == 0
  