How to use Faker from Factory_boy

Question

Factory_boy uses fake-factory (Faker) to generate random values, I would like to generate some random values in my Django tests using Faker directly.

Factory_boy docs suggests using factory.Faker and its provider as :

class RandomUserFactory(factory.Factory):
    class Meta:
        model = models.User

    first_name = factory.Faker('first_name')

But this isn't generating any name:

>>> import factory
>>> factory.Faker('name')
<factory.faker.Faker object at 0x7f1807bf5278>
>>> type(factory.Faker('name'))
<class 'factory.faker.Faker'>

From factory_boy faker.py class factory.Faker('ean', length=10) calls faker.Faker.ean(length=10) but Faker docs says it should show a name:

from faker import Faker
fake = Faker()
fake.name()
# 'Lucy Cechtelar'

Is there any other way to use Faker instead of setting an instance directly from Faker?

from faker import Factory
fake = Factory.create()
fake.name()

rlaszlo · Answer 1 · 2020-06-08T08:48:10.973

30

You can use faker with factory_boy like this:

class RandomUserFactory(factory.Factory):
    class Meta:
        model = models.User

    first_name = factory.Faker('first_name')

user = RandomUserFactory()

print user.first_name
# 'Emily'

So you need to instantiate a user with factory_boy and it will call Faker for you.

I don't know if you are trying to use this with Django or not, but if you want the factory to save the created user to the database, then you need to extend factory.django.DjangoModelFactory instead of factory.Factory.

edited Jun 08 '20 at 08:48

answered Aug 02 '16 at 12:15

rlaszlo

456
3
8

2

You just repeated what the OP already know. Maybe I misunderstand things here cause you have 25 upvotes ^^ – Nam G VU Aug 18 '21 at 10:24
@NamGVU I do repeat the class but the last 2 lines show how can you generate fake data trough the Factory instead of using the faker library directly. – rlaszlo Aug 18 '21 at 11:42

score 29 · Accepted Answer · answered Jan 22 '19 at 10:29

29

I know this is an old question but for anyone who might come across this, here's another approach that you can use.

>>> from factory.faker import faker
>>> FAKE = faker.Faker()
>>> FAKE.name()
'Scott Rodriguez'
>>> FAKE.address()
'PSC 5061, Box 1673\nAPO AP 53007'
>>>

answered Jan 22 '19 at 10:29

domino

2,137
1
22
30

2

This is what I wanted to know when I asked the question. – marcanuy Jan 22 '19 at 14:05
1

I think `from factory.faker import faker` is no different then [`import faker`](https://github.com/FactoryBoy/factory_boy/blob/v2.9.0/factory/faker.py#L22). From the standpoint of reproducibility I suppose it's better to use the instance that the `factory_boy` itself creates. – x-yuri Apr 06 '19 at 12:18
I agree with @x-yuri - it's nother related to the factoryboy's inner Faker – Nam G VU Aug 18 '21 at 10:21

x-yuri · Answer 3 · 2023-03-03T17:55:08.763

factory_boy doesn't provide a public/documented interface to get to the Faker instances it uses. So preferably create yourself a separate one. But in case you really need to:

import factory
print(factory.Faker._get_faker().random_int())
print(factory.Faker._get_faker('en_US').random_int())

You can also use generate()/evaluate(), but the interface changed with time:

# 3.0.1
# uses self.locale
print(factory.Faker('random_int').generate())
print(factory.Faker('random_int').evaluate(None, None, None))
print(factory.Faker('random_int', locale='en_US').generate())
print(factory.Faker('random_int', locale='en_US').evaluate(None, None, None))

# 3.1.0
# uses locale from the parameters
print(factory.Faker('random_int').generate({'locale': None}))
print(factory.Faker('random_int').evaluate(None, None, {'locale': None}))
print(factory.Faker('random_int').generate({'locale': 'en_US'}))
print(factory.Faker('random_int').evaluate(None, None, {'locale': 'en_US'}))

# 3.2.0, 3.2.1
# no generate()
print(factory.Faker('random_int').evaluate(None, None, {'locale': None}))
print(factory.Faker('random_int').evaluate(None, None, {'locale': 'en_US'}))

You may also check out the other answer for a more detailed example.

Is there anyway to avoid using private method _get_faker()? :) — hungneox, Feb 27 '23 at 06:48
@hungneox Updated the answer. That's all the options I can see. There's also [this answer](https://stackoverflow.com/a/38720172/52499), but I guess that's not what you want. — x-yuri, Mar 03 '23 at 17:57

score 4 · Answer 4 · answered Jul 25 '20 at 23:14

First, if you want to use factory_boy with a Django model, you should use DjangoModelFactory as it is recommended.

Second, factory_boy also suggests to use Faker attribute declaration in order to easily define realistic-looking factories. (see providers)

class RandomUserFactory(factory.DjangoModelFactory):
    class Meta:
        model = 'myapp.User'  # Equivalent to model = myapp.models.User

    first_name = factory.Faker('first_name')

Once you have defined your factory, you can simply use it as follows:

>>> o = RandomUserFactory()
>>> o.first_name
Tim

How would you do this if you are using a `LazyAttribute`? E.g. `factory.LazyAttribute(lambda a: factory.Faker('sentence')...` — alias51, Oct 15 '21 at 20:13

richardk · Answer 5 · 2022-04-24T23:40:21.260

3

As the other answers have already clarified, the proper/usual way to use Faker is with factories. However, it is occasionally useful to be able to use Faker inline, and that seems to be the underlying question here.

Here is an updated answer for 2022 and latest factoryboy versions:

from typing import Any

from factory import Faker


def get_fake(provider: str, locale: str | None = None) -> Any:
     """ e.g. `get_fake('name')` ==> 'Buzz Aldrin' """
    if not locale:
        locale = Faker._DEFAULT_LOCALE  # pylint: disable=protected-access
    return Faker(provider).evaluate({}, None, {'locale': locale})

edited Apr 24 '22 at 23:40

answered Apr 24 '22 at 23:25

richardk

151
1
7

It defaults to `Faker._DEFAULT_LOCALE` [anyway](https://github.com/FactoryBoy/factory_boy/blob/3.2.1/factory/faker.py#L65-L66). The first argument to `evaluate()` can be `None`. More info in [my answer](https://stackoverflow.com/a/55549083/52499). – x-yuri Mar 03 '23 at 18:01

How to use Faker from Factory_boy

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