How to create table during Django tests with managed = False

Question

I have a model with managed = False.

class SampleModel(models.Model):
    apple = models.CharField(max_length=30)
    orange = models.CharField(max_length=3         


        

Answer 1

You can use SchemaEditor in TestCase.setUp method to explicitly create models with managed = False.

# models.py

from django.db import models


class Unmanaged(models.Model):
    foo = models.TextField()

    class Meta:
        # This model is not managed by Django
        managed = False
        db_table = 'unmanaged_table'

And in your tests:

# tests.py

from django.db import connection
from django.test import TestCase

from myapp.models import Unmanaged


class ModelsTestCase(TestCase):
    def setUp(self):
        super().setUp()

        with connection.schema_editor() as schema_editor:
            schema_editor.create_model(Unmanaged)

            if Unmanaged._meta.db_table not in connection.introspection.table_names():
                raise ValueError("Table `{table_name}` is missing in test database.".format(table_name=Unmanaged._meta.db_table))

    def tearDown(self):
        super().tearDown()

        with connection.schema_editor() as schema_editor:
            schema_editor.delete_model(Unmanaged)

    def test_unmanaged_model(self):
        with self.assertNumQueries(num=3):
            self.assertEqual(0, Unmanaged.objects.all().count())
            Unmanaged.objects.create()
            self.assertEqual(1, Unmanaged.objects.all().count())

Answer 2

Execute raw SQL to create the table in the test setup:

from django.db import connection

class MyTest(unittest.TestCase):
    def setUp(self):
        connection.cursor().execute("CREATE TABLE ...")

    def tearDown(self):
        connection.cursor().execute("DROP TABLE ...")

Answer 3

Simply move your unmanaged models to a dedicated app and delete migrations folder. Details in my answer in Multi db and unmanged models - Test case are failing

Answer 4

Using pytest and pytest-django

To make this work (has been tested with django 3.0.2, pytest 5.3.5 and pytest-django 3.8.0):

1. Run your pytest with the additional argument --no-migrations.
2. Put the following code in your conftest.py. This has an unfortunate amount of copypasta, but I could not figure out how to first make my models unmanaged and then call the original django_db_setup. The issue of not being able to call pytest fixtures directly is discussed here: https://github.com/pytest-dev/pytest/issues/3950

conftest.py

# example file
import pytest
from pytest_django.fixtures import _disable_native_migrations


@pytest.fixture(scope="session")
def django_db_setup(
        request,
        django_test_environment,
        django_db_blocker,
        django_db_use_migrations,
        django_db_keepdb,
        django_db_createdb,
        django_db_modify_db_settings,
):
    # make unmanaged models managed
    from django.apps import apps
    unmanaged_models = []
    for app in apps.get_app_configs():
        unmanaged_models = [m for m in app.get_models()
                            if not m._meta.managed]
    for m in unmanaged_models:
        m._meta.managed = True

    # copypasta fixture code

    """Top level fixture to ensure test databases are available"""
    from pytest_django.compat import setup_databases, teardown_databases

    setup_databases_args = {}

    if not django_db_use_migrations:
        _disable_native_migrations()

    if django_db_keepdb and not django_db_createdb:
        setup_databases_args["keepdb"] = True

    with django_db_blocker.unblock():
        db_cfg = setup_databases(
            verbosity=request.config.option.verbose,
            interactive=False,
            **setup_databases_args
        )

    def teardown_database():
        with django_db_blocker.unblock():
            try:
                teardown_databases(db_cfg, verbosity=request.config.option.verbose)
            except Exception as exc:
                request.node.warn(
                    pytest.PytestWarning(
                        "Error when trying to teardown test databases: %r" % exc
                    )
                )

    if not django_db_keepdb:
        request.addfinalizer(teardown_database)

Answer 5

Create your own test runner using this:

from django.test.simple import DjangoTestSuiteRunner

class NoDbTestRunner(DjangoTestSuiteRunner):
  """ A test runner to test without database creation """

  def setup_databases(self, **kwargs):
    """ Override the database creation defined in parent class """
    #set manage=True for that specific database on here

Then on your settings add this class to TEST_RUNNER.

Answer 6

Nice plug and play solution. Just paste this before your test class definition. (note: django 1.8 used)

from django.db.models.loading import get_models

def change_managed_settings_just_for_tests():
  """django model managed bit needs to be switched for tests."""    

  unmanaged_models = [m for m in get_models() if not m._meta.managed]
  for m in unmanaged_models:
    m._meta.managed = True

change_managed_settings_just_for_tests()