My django project requires some model instances to be created at startup if they do not exist.
I currently create the required model instances I need in an app config.
class MyAppConfig(AppConfig):
name = 'my_app'
def ready(self):
create_required_objects()
def create_required_objects():
from my_app.models import MyObject
for name in MyObject.reserved_names:
if not MyObject.objects.filter(name=name).exists():
MyObject.objects.create(name=name, not_editable=True)
This works perfectly when the sqlite database is initialized, however if I clear the database and then try to run the sever, I get the following error:
django.db.utils.OperationalError: no such table: my_app_object
I would like to be able to clear the database (preferably by just removing db.sqlite3) and run the server.
Use post_migrate signal to create a new instance when migrating to the new database:
Like:
from django.db.models.signals import post_migrate
from my_app.models import MyObject
def create_required_objects(sender, **kwargs):
for name in MyObject.reserved_names:
if not MyObject.objects.filter(name=name).exists():
MyObject.objects.create(name=name, not_editable=True)
class MyAppConfig(AppConfig):
name = 'my_app'
def ready(self):
post_migrate.connect(create_required_objects ,sender=self)
This code automatically generates the user after migrating to the database.
You can use model_bakery to populate some temp data. You may need to do makemigrations and migrate to set up all tables in your database, you can follow this workflow.
python manage.py makemigrations
python manage.py migrate
In terms of populating data, you can try the following code:
from model_bakery import baker
from my_app.models import MyObject
baker.make(MyObject)
Add baker.make(MyObject) in your create_required_objects function after installation of model_bakery:
pip install model_bakery
I am trying to implement a many-to-many scenario using peewee python ORM and I'd like some unit tests. Peewee tutorial is great but it assumes that database is defined at module level then all models are using it. My situation is different: I don't have a source code file (a module from python's point of view) with tests which I run explicitly, I am using nose which collects tests from that file and runs them.
How do I use a custom database only for models instantiated in tests (which are being run by nose)? My goal is to use an in-memory database for tests only, to speedup the testing process.
I just pushed a commit today that makes this easier.
The fix is in the form of a context manager which allows you to override the database of a model:
from unittest import TestCase
from playhouse.test_utils import test_database
from peewee import *
from my_app.models import User, Tweet
test_db = SqliteDatabase(':memory:')
class TestUsersTweets(TestCase):
def create_test_data(self):
# ... create a bunch of users and tweets
for i in range(10):
User.create(username='user-%d' % i)
def test_timeline(self):
with test_database(test_db, (User, Tweet)):
# This data will be created in `test_db`
self.create_test_data()
# Perform assertions on test data inside ctx manager.
self.assertEqual(Tweet.timeline('user-0') [...])
# once we exit the context manager, we're back to using the normal database
See the documentation and have a look at the example testcases:
Context manager
Testcases showing how to use
To not include context manager in every test case, overwrite run method.
# imports and db declaration
class TestUsersTweets(TestCase):
def run(self, result=None):
with test_database(test_db, (User, Tweet)):
super(TestUsersTweets, self).run(result)
def test_timeline(self):
self.create_test_data()
self.assertEqual(Tweet.timeline('user-0') [...])
I took the great answers from #coleifer and #avalanchy and took them one step further.
In order to avoid overriding the run method on every TestCase subclass, you can use a base class... and I also like the idea of not having to write down every model class I work with, so I came up with this
import unittest
import inspect
import sys
import peewee
from abc import ABCMeta
from playhouse.test_utils import test_database
from business_logic.models import *
test_db = peewee.SqliteDatabase(':memory:')
class TestCaseWithPeewee(unittest.TestCase):
"""
This abstract class is used to "inject" the test database so that the tests don't use the real sqlite db
"""
__metaclass__ = ABCMeta
def run(self, result=None):
model_classes = [m[1] for m in inspect.getmembers(sys.modules['business_logic.models'], inspect.isclass) if
issubclass(m[1], peewee.Model) and m[1] != peewee.Model]
with test_database(test_db, model_classes):
super(TestCaseWithPeewee, self).run(result)
so, now I can just inherit from TestCaseWithPeewee and don't have to worry about anything else other than the test
Apparently, there's a new approach for the scenario described, where you can bind the models in the setUp() method of your test case:
Example from the official docs:
# tests.py
import unittest
from my_app.models import EventLog, Relationship, Tweet, User
MODELS = [User, Tweet, EventLog, Relationship]
# use an in-memory SQLite for tests.
test_db = SqliteDatabase(':memory:')
class BaseTestCase(unittest.TestCase):
def setUp(self):
# Bind model classes to test db. Since we have a complete list of
# all models, we do not need to recursively bind dependencies.
test_db.bind(MODELS, bind_refs=False, bind_backrefs=False)
test_db.connect()
test_db.create_tables(MODELS)
def tearDown(self):
# Not strictly necessary since SQLite in-memory databases only live
# for the duration of the connection, and in the next step we close
# the connection...but a good practice all the same.
test_db.drop_tables(MODELS)
# Close connection to db.
test_db.close()
# If we wanted, we could re-bind the models to their original
# database here. But for tests this is probably not necessary.
When using test_database I encountered problems with test_db not being initialized:
nose.proxy.Exception: Error, database not properly initialized before opening connection
-------------------- >> begin captured logging << --------------------
peewee: DEBUG: ('SELECT "t1"."id", "t1"."name", "t1"."count" FROM "counter" AS t1', [])
--------------------- >> end captured logging << ---------------------
I eventually fixed this by passing create_tables=True like so:
def test_timeline(self):
with test_database(test_db, (User, Tweet), create_tables=True):
# This data will be created in `test_db`
self.create_test_data()
According to the docs create_tables should default to True but it seems that isn't the case in the latest release of peewee.
For anyone who's using pytest, here's how I did it:
conftest.py
MODELS = [User, Tweet] # Also add get_through_model() for ManyToMany fields
test_db = SqliteDatabase(':memory:')
test_db.bind(MODELS, bind_refs=False, bind_backrefs=False)
test_db.connect()
test_db.create_tables(MODELS)
#pytest.fixture(autouse=True)
def in_mem_db(mocker):
mocked_db = mocker.patch("database.db", autospec=True) # "database.db" is where your app's code imports db from
mocked_db.return_value = test_db
return mocked_db
And voila, all your tests run with an in-memory sqlite database.
I'm trying to use a different set of configs for testing my django app (like, using in-memory sqlite3 instead of mysql) and for this purpose I'm trying to use another settings module. I run my tests this way:
python manage.py test --settings=test_settings
But Django seems to ignore my test_settings module. Am I doing something wrong?
Is test_settings a file or a directory?
Here's how I load different settings for tests. In settings.py, at the bottom:
# if manage.py test was called, use test settings
if 'test' in sys.argv:
try:
from test_settings import *
except ImportError:
pass
Super bonus! If you want to use sqlite3 for tests, you should activate integrity constraints, so you get the same foreign key exceptions as with mysql (lost of lot of time with this one). In some file of your project:
from django.db.backends.signals import connection_created
def activate_foreign_keys(sender, connection, **kwargs):
"""Enable integrity constraint with sqlite."""
if connection.vendor == 'sqlite':
cursor = connection.cursor()
cursor.execute('PRAGMA foreign_keys = ON;')
connection_created.connect(activate_foreign_keys)
I just bumped into this and confirm that on Django 1.6.1 --settings option is ignored.
I filed a ticket on the Django bug tracker:
https://code.djangoproject.com/ticket/21635#ticket
I have a Django app that requires a settings attribute in the form of:
RELATED_MODELS = ('appname1.modelname1.attribute1',
'appname1.modelname2.attribute2',
'appname2.modelname3.attribute3', ...)
Then hooks their post_save signal to update some other fixed model depending on the attributeN defined.
I would like to test this behaviour and tests should work even if this app is the only one in the project (except for its own dependencies, no other wrapper app need to be installed). How can I create and attach/register/activate mock models just for the test database? (or is it possible at all?)
Solutions that allow me to use test fixtures would be great.
You can put your tests in a tests/ subdirectory of the app (rather than a tests.py file), and include a tests/models.py with the test-only models.
Then provide a test-running script (example) that includes your tests/ "app" in INSTALLED_APPS. (This doesn't work when running app tests from a real project, which won't have the tests app in INSTALLED_APPS, but I rarely find it useful to run reusable app tests from a project, and Django 1.6+ doesn't by default.)
(NOTE: The alternative dynamic method described below only works in Django 1.1+ if your test case subclasses TransactionTestCase - which slows down your tests significantly - and no longer works at all in Django 1.7+. It's left here only for historical interest; don't use it.)
At the beginning of your tests (i.e. in a setUp method, or at the beginning of a set of doctests), you can dynamically add "myapp.tests" to the INSTALLED_APPS setting, and then do this:
from django.core.management import call_command
from django.db.models import loading
loading.cache.loaded = False
call_command('syncdb', verbosity=0)
Then at the end of your tests, you should clean up by restoring the old version of INSTALLED_APPS and clearing the app cache again.
This class encapsulates the pattern so it doesn't clutter up your test code quite as much.
#paluh's answer requires adding unwanted code to a non-test file and in my experience, #carl's solution does not work with django.test.TestCase which is needed to use fixtures. If you want to use django.test.TestCase, you need to make sure you call syncdb before the fixtures get loaded. This requires overriding the _pre_setup method (putting the code in the setUp method is not sufficient). I use my own version of TestCase that lets me add apps with test models. It is defined as follows:
from django.conf import settings
from django.core.management import call_command
from django.db.models import loading
from django import test
class TestCase(test.TestCase):
apps = ()
def _pre_setup(self):
# Add the models to the db.
self._original_installed_apps = list(settings.INSTALLED_APPS)
for app in self.apps:
settings.INSTALLED_APPS.append(app)
loading.cache.loaded = False
call_command('syncdb', interactive=False, verbosity=0)
# Call the original method that does the fixtures etc.
super(TestCase, self)._pre_setup()
def _post_teardown(self):
# Call the original method.
super(TestCase, self)._post_teardown()
# Restore the settings.
settings.INSTALLED_APPS = self._original_installed_apps
loading.cache.loaded = False
I shared my solution that I use in my projects. Maybe it helps someone.
pip install django-fake-model
Two simple steps to create fake model:
1) Define model in any file (I usualy define model in test file near a test case)
from django_fake_model import models as f
class MyFakeModel(f.FakeModel):
name = models.CharField(max_length=100)
2) Add decorator #MyFakeModel.fake_me to your TestCase or to test function.
class MyTest(TestCase):
#MyFakeModel.fake_me
def test_create_model(self):
MyFakeModel.objects.create(name='123')
model = MyFakeModel.objects.get(name='123')
self.assertEqual(model.name, '123')
This decorator creates table in your database before each test and remove the table after test.
Also you may create/delete table manually: MyFakeModel.create_table() / MyFakeModel.delete_table()
I've figured out a way for test-only models for django 1.7+.
The basic idea is, make your tests an app, and add your tests to INSTALLED_APPS.
Here's an example:
$ ls common
__init__.py admin.py apps.py fixtures models.py pagination.py tests validators.py views.py
$ ls common/tests
__init__.py apps.py models.py serializers.py test_filter.py test_pagination.py test_validators.py views.py
And I have different settings for different purposes(ref: splitting up the settings file), namely:
settings/default.py: base settings file
settings/production.py: for production
settings/development.py: for development
settings/testing.py: for testing.
And in settings/testing.py, you can modify INSTALLED_APPS:
settings/testing.py:
from default import *
DEBUG = True
INSTALLED_APPS += ['common', 'common.tests']
And make sure that you have set a proper label for your tests app, namely,
common/tests/apps.py
from django.apps import AppConfig
class CommonTestsConfig(AppConfig):
name = 'common.tests'
label = 'common_tests'
common/tests/__init__.py, set up proper AppConfig(ref: Django Applications).
default_app_config = 'common.tests.apps.CommonTestsConfig'
Then, generate db migration by
python manage.py makemigrations --settings=<your_project_name>.settings.testing tests
Finally, you can run your test with param --settings=<your_project_name>.settings.testing.
If you use py.test, you can even drop a pytest.ini file along with django's manage.py.
py.test
[pytest]
DJANGO_SETTINGS_MODULE=kungfu.settings.testing
Quoting from a related answer:
If you want models defined for testing only then you should check out
Django ticket #7835 in particular comment #24 part of which
is given below:
Apparently you can simply define models directly in your tests.py.
Syncdb never imports tests.py, so those models won't get synced to the
normal db, but they will get synced to the test database, and can be
used in tests.
This solution works only for earlier versions of django (before 1.7). You can check your version easily:
import django
django.VERSION < (1, 7)
Original response:
It's quite strange but form me works very simple pattern:
add tests.py to app which you are going to test,
in this file just define testing models,
below put your testing code (doctest or TestCase definition),
Below I've put some code which defines Article model which is needed only for tests (it exists in someapp/tests.py and I can test it just with: ./manage.py test someapp ):
class Article(models.Model):
title = models.CharField(max_length=128)
description = models.TextField()
document = DocumentTextField(template=lambda i: i.description)
def __unicode__(self):
return self.title
__test__ = {"doctest": """
#smuggling model for tests
>>> from .tests import Article
#testing data
>>> by_two = Article.objects.create(title="divisible by two", description="two four six eight")
>>> by_three = Article.objects.create(title="divisible by three", description="three six nine")
>>> by_four = Article.objects.create(title="divisible by four", description="four four eight")
>>> Article.objects.all().search(document='four')
[<Article: divisible by two>, <Article: divisible by four>]
>>> Article.objects.all().search(document='three')
[<Article: divisible by three>]
"""}
Unit tests also working with such model definition.
I chose a slightly different, albeit more coupled, approach to dynamically creating models just for testing.
I keep all my tests in a tests subdirectory that lives in my files app. The models.py file in the tests subdirectory contains my test-only models. The coupled part comes in here, where I need to add the following to my settings.py file:
# check if we are testing right now
TESTING = 'test' in sys.argv
if TESTING:
# add test packages that have models
INSTALLED_APPS += ['files.tests',]
I also set db_table in my test model, because otherwise Django would have created the table with the name tests_<model_name>, which may have caused a conflict with other test models in another app. Here's my my test model:
class Recipe(models.Model):
'''Test-only model to test out thumbnail registration.'''
dish_image = models.ImageField(upload_to='recipes/')
class Meta:
db_table = 'files_tests_recipe'
Here's the pattern that I'm using to do this.
I've written this method that I use on a subclassed version of TestCase. It goes as follows:
#classmethod
def create_models_from_app(cls, app_name):
"""
Manually create Models (used only for testing) from the specified string app name.
Models are loaded from the module "<app_name>.models"
"""
from django.db import connection, DatabaseError
from django.db.models.loading import load_app
app = load_app(app_name)
from django.core.management import sql
from django.core.management.color import no_style
sql = sql.sql_create(app, no_style(), connection)
cursor = connection.cursor()
for statement in sql:
try:
cursor.execute(statement)
except DatabaseError, excn:
logger.debug(excn.message)
pass
Then, I create a special test-specific models.py file in something like myapp/tests/models.py that's not included in INSTALLED_APPS.
In my setUp method, I call create_models_from_app('myapp.tests') and it creates the proper tables.
The only "gotcha" with this approach is that you don't really want to create the models ever time setUp runs, which is why I catch DatabaseError. I guess the call to this method could go at the top of the test file and that would work a little better.
Combining your answers, specially #slacy's, I did this:
class TestCase(test.TestCase):
initiated = False
#classmethod
def setUpClass(cls, *args, **kwargs):
if not TestCase.initiated:
TestCase.create_models_from_app('myapp.tests')
TestCase.initiated = True
super(TestCase, cls).setUpClass(*args, **kwargs)
#classmethod
def create_models_from_app(cls, app_name):
"""
Manually create Models (used only for testing) from the specified string app name.
Models are loaded from the module "<app_name>.models"
"""
from django.db import connection, DatabaseError
from django.db.models.loading import load_app
app = load_app(app_name)
from django.core.management import sql
from django.core.management.color import no_style
sql = sql.sql_create(app, no_style(), connection)
cursor = connection.cursor()
for statement in sql:
try:
cursor.execute(statement)
except DatabaseError, excn:
logger.debug(excn.message)
With this, you don't try to create db tables more than once, and you don't need to change your INSTALLED_APPS.
If you are writing a reusable django-app, create a minimal test-dedicated app for it!
$ django-admin.py startproject test_myapp_project
$ django-admin.py startapp test_myapp
add both myapp and test_myapp to the INSTALLED_APPS, create your models there and it's good to go!
I have gone through all these answers as well as django ticket 7835, and I finally went for a totally different approach.
I wanted my app (somehow extending queryset.values() ) to be able to be tested in isolation; also, my package does include some models and I wanted a clean distinction between test models and package ones.
That's when I realized it was easier to add a very small django project in the package!
This also allows a much cleaner separation of code IMHO:
In there you can cleanly and without any hack define your models, and you know they will be created when you run your tests from in there!
If you are not writing an independent, reusable app you can still go this way: create a test_myapp app, and add it to your INSTALLED_APPS only in a separate settings_test_myapp.py!
Someone already mentioned Django ticket #7835, but there appears to be a more recent reply that looks much more promising for more recent versions of Django. Specifically #42, which proposes a different TestRunner:
from importlib.util import find_spec
import unittest
from django.apps import apps
from django.conf import settings
from django.test.runner import DiscoverRunner
class TestLoader(unittest.TestLoader):
""" Loader that reports all successful loads to a runner """
def __init__(self, *args, runner, **kwargs):
self.runner = runner
super().__init__(*args, **kwargs)
def loadTestsFromModule(self, module, pattern=None):
suite = super().loadTestsFromModule(module, pattern)
if suite.countTestCases():
self.runner.register_test_module(module)
return suite
class RunnerWithTestModels(DiscoverRunner):
""" Test Runner that will add any test packages with a 'models' module to INSTALLED_APPS.
Allows test only models to be defined within any package that contains tests.
All test models should be set with app_label = 'tests'
"""
def __init__(self, *args, **kwargs):
self.test_packages = set()
self.test_loader = TestLoader(runner=self)
super().__init__(*args, **kwargs)
def register_test_module(self, module):
self.test_packages.add(module.__package__)
def setup_databases(self, **kwargs):
# Look for test models
test_apps = set()
for package in self.test_packages:
if find_spec('.models', package):
test_apps.add(package)
# Add test apps with models to INSTALLED_APPS that aren't already there
new_installed = settings.INSTALLED_APPS + tuple(ta for ta in test_apps if ta not in settings.INSTALLED_APPS)
apps.set_installed_apps(new_installed)
return super().setup_databases(**kwargs)