Customisation

• The fake.FAKER is an instance of the fake.Faker class.

• The fake.FACTORY is an instance of the fake.Factory class, initialised with the fake.FAKER instance.

The Faker class is easy to customise. See the following example:

Filename: custom_fake.py

import random
import string

from fake import Faker, Factory, provider


# Custom first names dictionary
FIRST_NAMES = [
    "Anahit",
    "Ani",
    "Aram",
    "Areg",
    "Artur",
    "Astghik",
    "Atom",
    "Barsegh",
    "Gaiane",
    "Gor",
    "Hakob",
    "Hasmik",
    "Levon",
    "Lilit",
    "Mariam",
    "Nare",
    "Narek",
    "Nune",
    "Raffi",
    "Shant",
    "Tatev",
    "Tigran",
    "Vahan",
    "Vardan",
]

# Custom last names dictionary
LAST_NAMES = [
    "Amatouni",
    "Avagyan",
    "Danielyan",
    "Egoyan",
    "Gevorgyan",
    "Gnouni",
    "Grigoryan",
    "Hakobyan",
    "Harutyunyan",
    "Hovhannisyan",
    "Karapetyan",
    "Khachatryan",
    "Manukyan",
    "Melikyan",
    "Mkrtchyan",
    "Petrosyan",
    "Sahakyants",
    "Sargsyan",
    "Saroyan",
    "Sedrakyan",
    "Simonyan",
    "Stepanyan",
    "Ter-Martirosyan",
    "Vardanyan",
]

# Custom words dictionary
WORDS = [
    "time", "person", "year", "way", "day", "thing", "man", "world",
    "life", "hand", "part", "child", "eye", "woman", "place", "work",
    "week", "case", "point", "government", "company", "number", "group",
    "problem", "fact", "be", "have", "do", "say", "get", "make", "go",
    "know", "take", "see", "come", "think", "look", "want", "give",
    "use", "find", "tell", "ask", "work", "seem", "feel", "try", "leave",
    "call", "good", "new", "first", "last", "long", "great", "little",
    "own", "other", "old", "right", "big", "high", "different", "small",
    "large", "next", "early", "young", "important", "few", "public",
    "bad", "same", "able", "to", "of", "in", "for", "on", "with", "as",
    "at", "by", "from", "up", "about", "into", "over", "after",
    "beneath", "under", "above", "the", "and", "a", "that", "I", "it",
    "not",
]

STREET_NAMES = [
    "Bosweg",
    "Groningerweg",
    "Jasmijnstraat",
    "Noordstraat",
    "Ooststraat",
    "Oranjestraat",
    "Prinsengracht",
    "Ringweg",
    "Weststraat",
    "Zonnelaan",
    "Zuidstraat",
]

CITIES = [
    "Amsterdam",
    "Delft",
    "Den Haag",
    "Groningen",
    "Leiden",
    "Nijmegen",
]

REGIONS = [
    "Friesland",
    "Groningen",
    "Limburg",
    "Utrecht",
]


class CustomFaker(Faker):
    """Custom Faker class."""

    def load_names(self) -> None:
        """Override default first- and last-names dictionaries."""
        self._first_names = FIRST_NAMES
        self._last_names = LAST_NAMES

    def load_words(self) -> None:
        """Override default words dictionary."""
        self._words = WORDS

    @provider
    def address_line(self) -> str:
        """Generate a random Dutch address line like 'Oranjestraat 1'.

        :return: A randomly generated Dutch address line as a string.
        """
        # Generate components of the address
        street = random.choice(STREET_NAMES)
        house_number = random.randint(1, 200)
        suffixes = [""] * 10 + ["A", "B", "C"]  # Optional suffixes
        suffix = random.choice(suffixes)

        # Combine components into a Dutch address format
        return f"{street} {house_number}{suffix}"

    @provider
    def city(self) -> str:
        return random.choice(CITIES)

    @provider
    def region(self) -> str:
        return random.choice(REGIONS)

    @provider
    def postal_code(self) -> str:
        """Generate a random Dutch postal code in the format '1234 AB'.

        :return: A randomly generated Dutch postal code as a string.
        """
        number_part = "".join(random.choices(string.digits, k=4))
        letter_part = "".join(random.choices(string.ascii_uppercase, k=2))
        return f"{number_part} {letter_part}"


FAKER = CustomFaker()
FACTORY = Factory(FAKER)

The postal_code is the provider method and shall be decorated with @provider decorator.

You can now use both FAKER and FACTORY as you would normally do.

---

Filename: models.py

from dataclasses import dataclass
from datetime import date


@dataclass
class Address:
    id: int
    address_line: str
    postal_code: str
    city: str
    region: str

    def __str__(self) -> str:
        return self.address_line


@dataclass
class Person:
    id: int
    first_name: str
    last_name: str
    email: str
    dob: date
    address: Address

    def __str__(self) -> str:
        return self.username

---

Filename: factories.py

from fake import ModelFactory, SubFactory, post_save, pre_save

# Import defined ORM models and customised FACTORY instance:
# from models import Address, Person
# from custom_fake import FACTORY


class AddressFactory(ModelFactory):
    id = FACTORY.pyint()
    address_line = FACTORY.address_line()
    postal_code = FACTORY.postal_code()
    city = FACTORY.city()
    region = FACTORY.region()

    class Meta:
        model = Address


class PersonFactory(ModelFactory):
    id = FACTORY.pyint()
    first_name = FACTORY.first_name()
    last_name = FACTORY.last_name()
    email = FACTORY.email()
    dob = FACTORY.date()
    address = SubFactory(AddressFactory)

    class Meta:
        model = Person

---

And this is how you could use it:

address = AddressFactory()
assert isinstance(address, Address)
assert address.city in CITIES
assert address.region in REGIONS

person = PersonFactory()
assert isinstance(person, Person)
assert person.first_name in FIRST_NAMES
assert person.last_name in LAST_NAMES

---