Pytest fixtures#
Polyfactory support registering factories as pytest fixtures using the
register_fixture
decorator:
from dataclasses import dataclass
from datetime import date, datetime
from typing import List, Optional, Union
from uuid import UUID
from polyfactory.factories import DataclassFactory
from polyfactory.pytest_plugin import register_fixture
@dataclass
class Person:
id: UUID
name: str
hobbies: Optional[List[str]]
nicks: List[str]
age: Union[float, int]
birthday: Union[datetime, date]
@register_fixture
class PersonFactory(DataclassFactory[Person]):
...
def test_person_factory(person_factory: PersonFactory) -> None:
person_instance = person_factory.build()
assert isinstance(person_instance, Person)
In the above example the PersonFactory
is wrapped as a pytest fixture. As a result it cannot be used as a normal
factory,because pytest fixtures are callables that must be called by pytest. To overcome this restriction, you can
declare the fixture separately from the declaration of the class:
from dataclasses import dataclass
from datetime import date, datetime
from typing import List, Optional, Union
from uuid import UUID
from polyfactory.factories import DataclassFactory
from polyfactory.pytest_plugin import register_fixture
@dataclass
class Person:
id: UUID
name: str
hobbies: Optional[List[str]]
nicks: List[str]
age: Union[float, int]
birthday: Union[datetime, date]
class PersonFactory(DataclassFactory[Person]):
...
person_factory_fixture = register_fixture(PersonFactory)
def test_person_factory(person_factory: PersonFactory) -> None:
person_instance = person_factory.build()
assert isinstance(person_instance, Person)
# we can still access the factory class itself-
another_person_instance = PersonFactory.build()
assert isinstance(another_person_instance, Person)
You can also control the name of the fixture using the optional name
kwarg:
from dataclasses import dataclass
from datetime import date, datetime
from typing import List, Optional, Union
from uuid import UUID
from polyfactory.factories import DataclassFactory
from polyfactory.pytest_plugin import register_fixture
@dataclass
class Person:
id: UUID
name: str
hobbies: Optional[List[str]]
nicks: List[str]
age: Union[float, int]
birthday: Union[datetime, date]
class PersonFactory(DataclassFactory[Person]):
...
person_factory_fixture = register_fixture(PersonFactory, name="aliased_person_factory")
def test_person_factory(aliased_person_factory: PersonFactory) -> None:
person_instance = aliased_person_factory.build()
assert isinstance(person_instance, Person)
The Fixture
Field#
You can also use factory fixtures as factory fields using the Fixture
:
from dataclasses import dataclass
from datetime import date, datetime
from typing import List, Optional, Union
from uuid import UUID
from polyfactory import Fixture
from polyfactory.factories import DataclassFactory
from polyfactory.pytest_plugin import register_fixture
@dataclass
class Person:
id: UUID
name: str
hobbies: Optional[List[str]]
nicks: List[str]
age: Union[float, int]
birthday: Union[datetime, date]
@dataclass
class ClassRoom:
teacher: Person
pupils: List[Person]
@register_fixture
class PersonFactory(DataclassFactory[Person]):
...
class ClassRoomFactory(DataclassFactory[ClassRoom]):
teacher = Fixture(PersonFactory, name="Ludmilla Newman")
pupils = Fixture(PersonFactory, size=20)
def test_fixture_field() -> None:
classroom_instance = ClassRoomFactory.build()
assert isinstance(classroom_instance.teacher, Person)
assert classroom_instance.teacher.name == "Ludmilla Newman"
assert len(classroom_instance.pupils) == 20
Fixture
is similar to Use
in that it accepts kwargs that are propagated the to the build or batch methods of the
factory.