[Answered ]-Django pytest database access for data migration

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I found the solution thanks to @Håken Lid and the Django issue he provided. The problem is that Django creates the ContentTypes receiving a signal emitted when all the migrations complete. That’s why it didn’t find the permissions but it let me create the groups.

To solve the problem we have to manually send the signal inside our data migration.

# -*- coding: utf-8 -*-
# Generated by Django 1.9.6 on 2016-06-07 09:56
from __future__ import unicode_literals

from django.core.management.sql import emit_post_migrate_signal
from django.db import migrations


def create_groups(apps, schema_editor):
    # Send the signal to create the permissions
    db_alias = schema_editor.connection.alias
    try:
        # Django 1.9
        emit_post_migrate_signal(2, False, db_alias)
    except TypeError:
        # Django < 1.9
        try:
            # Django 1.8
            emit_post_migrate_signal(2, False, 'default', db_alias)
        except TypeError:  # Django < 1.8
            emit_post_migrate_signal([], 2, False, 'default', db_alias)

    Group = apps.get_model('auth', 'group')
    Permission = apps.get_model('auth', 'permission')

    group1 = Group.objects.create(name='grou1')
    group1_permissions = Permission.objects.filter(codename__in=[
        'add_app1_model',
        'add_app2_model',
        'custom_permission_app1_model'
    ])
    group1.permissions.add(*list(group1_permissions))

    group2 = Group.objects.create(name='group2')
    group2_permissions = Permission.objects.get(
        codename='custom_permission_app2_model'    
    )
    group2.permissions.add(*list(group2_permissions))


class Migration(migrations.Migration):

    dependencies = [
        ('app1', '0001'),
        ('app2', '0001'),
        ('contenttypes', '__latest__'),
        ('sites', '__latest__')
    ]

    operations = [
        migrations.RunPython(create_groups)
    ]

In the snipped we send the signal before accessing the Permissions and we include the latest contenttypes and sites apps migrations as dependencies.

👤alejandrodnm

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