The Mixer is a helper to generate instances of Django or SQLAlchemy models. It's useful for testing and fixture replacement. Fast and convenient test-data generation.

Mixer supports:

• Django;
• SQLAlchemy;
• Flask-SQLAlchemy;
• Peewee;
• Pony;
• Mongoengine;
• Marshmallow;
• Custom schemes;

Docs are available at https://mixer.readthedocs.org/. Pull requests with documentation enhancements and/or fixes are awesome and most welcome.

Описание на русском языке: http://klen.github.io/mixer.html

Important

From version 6.2 the Mixer library doesn't support Python 2. The latest version with python<3 support is mixer 6.1.3

Contents

• Requirements
• Installation
• Usage
  • Django workflow
  • Flask, Flask-SQLAlchemy
    • Support for Flask-SQLAlchemy models that have __init__ arguments
  • SQLAlchemy workflow
  • Mongoengine workflow
  • Marshmallow workflow
  • Common usage
  • DB commits
  • Custom fields
  • Middlewares
  • Locales
• Bug tracker
• Contributing
• Contributors
• License

Requirements

• Python 3.7+
• Django (3.0, 3.1) for Django ORM support;
• Flask-SQLALchemy for SQLAlchemy ORM support and integration as Flask application;
• Faker >= 0.7.3
• Mongoengine for Mongoengine ODM support;
• SQLAlchemy for SQLAlchemy ORM support;
• Peewee ORM support;

Installation

Mixer should be installed using pip:

pip install mixer

Usage

By default Mixer tries to generate fake (human-friendly) data.

If you want to randomize the generated values initialize the Mixer

by manual: Mixer(fake=False)

By default Mixer saves the generated objects in a database. If you want to disable

this, initialize the Mixer by manual like Mixer(commit=False)

Django workflow

Quick example:

from mixer.backend.django import mixer
from customapp.models import User, UserMessage

# Generate a random user
user = mixer.blend(User)

# Generate an UserMessage
message = mixer.blend(UserMessage, user=user)

# Generate an UserMessage and an User. Set username for generated user to 'testname'.
message = mixer.blend(UserMessage, user__username='testname')

# Generate SomeModel from SomeApp and select FK or M2M values from db
some = mixer.blend('someapp.somemodel', somerelation=mixer.SELECT)

# Generate SomeModel from SomeApp and force a value of money field from default to random
some = mixer.blend('someapp.somemodel', money=mixer.RANDOM)

# Generate SomeModel from SomeApp and skip the generation of money field
some = mixer.blend('someapp.somemodel', money=mixer.SKIP)

# Generate 5 SomeModel's instances and take company field's values from custom generator
some_models = mixer.cycle(5).blend('somemodel', company=(name for name in company_names))

Flask, Flask-SQLAlchemy

Quick example:

from mixer.backend.flask import mixer
from models import User, UserMessage

mixer.init_app(self.app)

# Generate a random user
user = mixer.blend(User)

# Generate an userMessage
message = mixer.blend(UserMessage, user=user)

# Generate an UserMessage and an User. Set username for generated user to 'testname'.
message = mixer.blend(UserMessage, user__username='testname')

# Generate SomeModel and select FK or M2M values from db
some = mixer.blend('project.models.SomeModel', somerelation=mixer.SELECT)

# Generate SomeModel from SomeApp and force a value of money field from default to random
some = mixer.blend('project.models.SomeModel', money=mixer.RANDOM)

# Generate SomeModel from SomeApp and skip the generation of money field
some = mixer.blend('project.models.SomeModel', money=mixer.SKIP)

# Generate 5 SomeModel's instances and take company field's values from custom generator
some_models = mixer.cycle(5).blend('project.models.SomeModel', company=(company for company in companies))

Support for Flask-SQLAlchemy models that have __init__ arguments

For support this scheme, just create your own mixer class, like this:

from mixer.backend.sqlalchemy import Mixer

class MyOwnMixer(Mixer):

    def populate_target(self, values):
        target = self.__scheme(**values)
        return target

mixer = MyOwnMixer()

SQLAlchemy workflow

Example of initialization:

from mixer.backend.sqlalchemy import Mixer

ENGINE = create_engine('sqlite:///:memory:')
BASE = declarative_base()
SESSION = sessionmaker(bind=ENGINE)

mixer = Mixer(session=SESSION(), commit=True)
role = mixer.blend('package.models.Role')

Also, see Flask, Flask-SQLAlchemy.

Mongoengine workflow

Example usage:

from mixer.backend.mongoengine import mixer

class User(Document):
    created_at = DateTimeField(default=datetime.datetime.now)
    email = EmailField(required=True)
    first_name = StringField(max_length=50)
    last_name = StringField(max_length=50)
    username = StringField(max_length=50)

class Post(Document):
    title = StringField(max_length=120, required=True)
    author = ReferenceField(User)
    tags = ListField(StringField(max_length=30))

post = mixer.blend(Post, author__username='foo')

Marshmallow workflow

Example usage:

from mixer.backend.marshmallow import mixer
import marshmallow as ma

class User(ma.Schema):
    created_at = ma.fields.DateTime(required=True)
    email = ma.fields.Email(required=True)
    first_name = ma.fields.String(required=True)
    last_name = ma.fields.String(required=True)
    username = ma.fields.String(required=True)

class Post(ma.Schema):
    title = ma.fields.String(required=True)
    author = ma.fields.Nested(User, required=True)

post = mixer.blend(Post, author__username='foo')

Common usage

Quick example:

from mixer.main import mixer

class Test:
    one = int
    two = int
    name = str

class Scheme:
    name = str
    money = int
    male = bool
    prop = Test

scheme = mixer.blend(Scheme, prop__one=1)

DB commits

By default 'django', 'flask', 'mongoengine' backends tries to save objects in database. For preventing this behavior init mixer manually:

from mixer.backend.django import Mixer

mixer = Mixer(commit=False)

Or you can temporary switch context use the mixer as context manager:

from mixer.backend.django import mixer

# Will be save to db
user1 = mixer.blend('auth.user')

# Will not be save to db
with mixer.ctx(commit=False):
    user2 = mixer.blend('auth.user')

Custom fields

The mixer allows you to define generators for fields by manually. Quick example:

from mixer.main import mixer

class Test:
    id = int
    name = str

mixer.register(Test,
    name=lambda: 'John',
    id=lambda: str(mixer.faker.small_positive_integer())
)

test = mixer.blend(Test)
test.name == 'John'
isinstance(test.id, str)

# You could pinned just a value to field
mixer.register(Test, name='Just John')
test = mixer.blend(Test)
test.name == 'Just John'

Also, you can make your own factory for field types:

from mixer.backend.django import Mixer, GenFactory

def get_func(*args, **kwargs):
    return "Always same"

class MyFactory(GenFactory):
    generators = {
        models.CharField: get_func
    }

mixer = Mixer(factory=MyFactory)

Middlewares

You can add middleware layers to process generation:

from mixer.backend.django import mixer

# Register middleware to model
@mixer.middleware('auth.user')
def encrypt_password(user):
    user.set_password('test')
    return user

You can add several middlewares. Each middleware should get one argument (generated value) and return them.

It's also possible to unregister a middleware:

mixer.unregister_middleware(encrypt_password)

Locales

By default mixer uses 'en' locale. You could switch mixer default locale by creating your own mixer:

from mixer.backend.django import Mixer

mixer = Mixer(locale='it')
mixer.faker.name()          ## u'Acchisio Conte'

At any time you could switch mixer current locale:

mixer.faker.locale = 'cz'
mixer.faker.name()          ## u'Miloslava Urbanov\xe1 CSc.'

mixer.faker.locale = 'en'
mixer.faker.name()          ## u'John Black'

# Use the mixer context manager
mixer.faker.phone()         ## u'1-438-238-1116'
with mixer.ctx(locale='fr'):
    mixer.faker.phone()     ## u'08 64 92 11 79'

mixer.faker.phone()         ## u'1-438-238-1116'

Bug tracker

If you have any suggestions, bug reports or annoyances please report them to the issue tracker at https://github.com/klen/mixer/issues

Contributing

Development of mixer happens at Github: https://github.com/klen/mixer

Contributors

• Antoine Bertin (https://github.com/Diaoul)
• Benjamin Port (https://github.com/bport)
• Dmitriy Moseev (https://github.com/DmitriyMoseev)
• Eelke Hermens (https://github.com/eelkeh)
• Esteban J. G. Gabancho (https://github.com/egabancho)
• Felix Dreissig (https://github.com/F30)
• Illia Volochii (https://github.com/illia-v)
• Jannis (https://github.com/jnns)
• Kirill Pavlov (https://github.com/pavlov99)
• Kwok-kuen Cheung (https://github.com/cheungpat)
• Mahdi Yusuf (https://github.com/myusuf3)
• Marek Baczyński (https://github.com/imbaczek)
• Marigold (https://github.com/Marigold)
• Matt Caldwell (https://github.com/mattcaldwell)
• Mikhail Porokhovnichenko (https://github.com/marazmiki)
• Skylar Saveland (https://github.com/skyl)
• Suriya Subramanian (https://github.com/suriya)
• Gram (https://github.com/orsinium)
• Joshua (https://github.com/jomasti)
• Lucas Rangel Cezimbra (https://github.com/lucasrcezimbra)
• avi-pomicell (https://github.com/avi-pomicell)
• Jochen Brissier (https://github.com/jbrissier)

License

Licensed under a BSD license.