Refs #25746 -- Added a test utility to isolate inlined model registration. (7bb373e3) · Commits · Dom Sekotill / django

django/db/models/options.py

+3 −1

Original line number	Diff line number	Diff line
		@@ -69,6 +69,8 @@ class Options(object):
		'local_concrete_fields', '_forward_fields_map'}
		REVERSE_PROPERTIES = {'related_objects', 'fields_map', '_relation_tree'}

		default_apps = apps

		def __init__(self, meta, app_label=None):
		self._get_fields_cache = {}
		self.local_fields = []
		@@ -124,7 +126,7 @@ class Options(object):
		self.related_fkey_lookups = []

		# A custom app registry to use, if you're making a separate model set.
		self.apps = apps
		self.apps = self.default_apps

		self.default_related_name = None

django/test/utils.py

+68 −0

Original line number	Diff line number	Diff line
		@@ -9,10 +9,12 @@ from unittest import skipIf, skipUnless
		from xml.dom.minidom import Node, parseString

		from django.apps import apps
		from django.apps.registry import Apps
		from django.conf import UserSettingsHolder, settings
		from django.core import mail
		from django.core.signals import request_started
		from django.db import reset_queries
		from django.db.models.options import Options
		from django.http import request
		from django.template import Template
		from django.test.signals import setting_changed, template_rendered
		@@ -640,3 +642,69 @@ class LoggingCaptureMixin(object):

		def tearDown(self):
		self.logger.handlers[0].stream = self.old_stream


		class isolate_apps(object):
		"""
		Act as either a decorator or a context manager to register models defined
		in its wrapped context to an isolated registry.

		The list of installed apps the isolated registry should contain must be
		passed as arguments.

		Two optional keyword arguments can be specified:

		`attr_name`: attribute assigned the isolated registry if used as a class
		decorator.

		`kwarg_name`: keyword argument passing the isolated registry to the
		decorated method.
		"""

		def __init__(self, installed_apps, *kwargs):
		self.installed_apps = installed_apps
		self.attr_name = kwargs.pop('attr_name', None)
		self.kwarg_name = kwargs.pop('kwarg_name', None)

		def enable(self):
		self.old_apps = Options.default_apps
		apps = Apps(self.installed_apps)
		setattr(Options, 'default_apps', apps)
		return apps

		def disable(self):
		setattr(Options, 'default_apps', self.old_apps)

		def __enter__(self):
		return self.enable()

		def __exit__(self, exc_type, exc_value, traceback):
		self.disable()

		def __call__(self, decorated):
		if isinstance(decorated, type):
		# A class is decorated
		decorated_setUp = decorated.setUp
		decorated_tearDown = decorated.tearDown

		def setUp(inner_self):
		apps = self.enable()
		if self.attr_name:
		setattr(inner_self, self.attr_name, apps)
		decorated_setUp(inner_self)

		def tearDown(inner_self):
		decorated_tearDown(inner_self)
		self.disable()

		decorated.setUp = setUp
		decorated.tearDown = tearDown
		return decorated
		else:
		@wraps(decorated)
		def inner(args, *kwargs):
		with self as apps:
		if self.kwarg_name:
		kwargs[self.kwarg_name] = apps
		return decorated(args, *kwargs)
		return inner

docs/internals/contributing/writing-code/unit-tests.txt

+114 −0

Original line number	Diff line number	Diff line
		@@ -303,3 +303,117 @@ purpose.

		Support for running tests in parallel and the ``--parallel`` option were
		added.

		Tips for writing tests
		----------------------

		.. highlight:: python

		Isolating model registration
		~~~~~~~~~~~~~~~~~~~~~~~~~~~~

		To avoid polluting the global :attr:`~django.apps.apps` registry and prevent
		unnecessary table creation, models defined in a test method should be bound to
		a temporary ``Apps`` instance::

		from django.apps.registry import Apps
		from django.db import models
		from django.test import SimpleTestCase

		class TestModelDefinition(SimpleTestCase):
		def test_model_definition(self):
		test_apps = Apps(['app_label'])

		class TestModel(models.Model):
		class Meta:
		apps = test_apps
		...

		.. function:: django.test.utils.isolate_apps(*app_labels, attr_name=None, kwarg_name=None)

		.. versionadded:: 1.10

		Since this pattern involves a lot of boilerplate, Django provides the
		:func:`~django.test.utils.isolate_apps` decorator. It's used like this::

		from django.db import models
		from django.test import SimpleTestCase
		from django.test.utils import isolate_apps

		class TestModelDefinition(SimpleTestCase):
		@isolate_apps('app_label')
		def test_model_definition(self):
		class TestModel(models.Model):
		pass
		...

		.. admonition:: Setting ``app_label``

		Models defined in a test method with no explicit
		:attr:`~django.db.models.Options.app_label` are automatically assigned the
		label of the app in which their test class is located.

		In order to make sure the models defined within the context of
		:func:`~django.test.utils.isolate_apps` instances are correctly
		installed, you should pass the set of targeted ``app_label`` as arguments:

		.. snippet::
		:filename: tests/app_label/tests.py

		from django.db import models
		from django.test import SimpleTestCase
		from django.test.utils import isolate_apps

		class TestModelDefinition(SimpleTestCase):
		@isolate_apps('app_label', 'other_app_label')
		def test_model_definition(self):
		# This model automatically receives app_label='app_label'
		class TestModel(models.Model):
		pass

		class OtherAppModel(models.Model):
		class Meta:
		app_label = 'other_app_label'
		...

		The decorator can also be applied to classes::

		from django.db import models
		from django.test import SimpleTestCase
		from django.test.utils import isolate_apps

		@isolate_apps('app_label')
		class TestModelDefinition(SimpleTestCase):
		def test_model_definition(self):
		class TestModel(models.Model):
		pass
		...

		The temporary ``Apps`` instance used to isolate model registration can be
		retrieved as an attribute when used as a class decorator by using the
		``attr_name`` parameter::

		from django.db import models
		from django.test import SimpleTestCase
		from django.test.utils import isolate_apps

		@isolate_apps('app_label', attr_name='apps')
		class TestModelDefinition(SimpleTestCase):
		def test_model_definition(self):
		class TestModel(models.Model):
		pass
		self.assertIs(self.apps.get_model('app_label', 'TestModel'), TestModel)

		Or as an argument on the test method when used as a method decorator by using
		the ``kwarg_name`` parameter::

		from django.db import models
		from django.test import SimpleTestCase
		from django.test.utils import isolate_apps

		class TestModelDefinition(SimpleTestCase):
		@isolate_apps('app_label', kwarg_name='apps')
		def test_model_definition(self, apps):
		class TestModel(models.Model):
		pass
		self.assertIs(apps.get_model('app_label', 'TestModel'), TestModel)

tests/test_utils/tests.py

+41 −2

Original line number	Diff line number	Diff line
		@@ -8,7 +8,7 @@ from django.conf.urls import url
		from django.contrib.staticfiles.finders import get_finder, get_finders
		from django.contrib.staticfiles.storage import staticfiles_storage
		from django.core.files.storage import default_storage
		from django.db import connection, router
		from django.db import connection, models, router
		from django.forms import EmailField, IntegerField
		from django.http import HttpResponse
		from django.template.loader import render_to_string
		@@ -17,7 +17,9 @@ from django.test import (
		skipUnlessDBFeature,
		)
		from django.test.html import HTMLParseError, parse_html
		from django.test.utils import CaptureQueriesContext, override_settings
		from django.test.utils import (
		CaptureQueriesContext, isolate_apps, override_settings,
		)
		from django.urls import NoReverseMatch, reverse
		from django.utils import six
		from django.utils._os import abspathu
		@@ -1029,3 +1031,40 @@ class AllowedDatabaseQueriesTests(SimpleTestCase):

		def test_allowed_database_queries(self):
		Car.objects.first()


		@isolate_apps('test_utils', attr_name='class_apps')
		class IsolatedAppsTests(SimpleTestCase):
		def test_installed_apps(self):
		self.assertEqual([app_config.label for app_config in self.class_apps.get_app_configs()], ['test_utils'])

		def test_class_decoration(self):
		class ClassDecoration(models.Model):
		pass
		self.assertEqual(ClassDecoration._meta.apps, self.class_apps)

		@isolate_apps('test_utils', kwarg_name='method_apps')
		def test_method_decoration(self, method_apps):
		class MethodDecoration(models.Model):
		pass
		self.assertEqual(MethodDecoration._meta.apps, method_apps)

		def test_context_manager(self):
		with isolate_apps('test_utils') as context_apps:
		class ContextManager(models.Model):
		pass
		self.assertEqual(ContextManager._meta.apps, context_apps)

		@isolate_apps('test_utils', kwarg_name='method_apps')
		def test_nested(self, method_apps):
		class MethodDecoration(models.Model):
		pass
		with isolate_apps('test_utils') as context_apps:
		class ContextManager(models.Model):
		pass
		with isolate_apps('test_utils') as nested_context_apps:
		class NestedContextManager(models.Model):
		pass
		self.assertEqual(MethodDecoration._meta.apps, method_apps)
		self.assertEqual(ContextManager._meta.apps, context_apps)
		self.assertEqual(NestedContextManager._meta.apps, nested_context_apps)