Testcase for testing migrations conflicts

test_migrations_conflicts.py

"""
To speedup tests many developers disables migrations in tests
F.e.
  apps = [app.split('.')[-1] for app in INSTALLED_APPS]
  MIGRATION_MODULES = {app: "%s.skip_migrations" % app for app in apps}
But bad thing about it that migrations aren't being tested for conflicts
until we run manage.py migrations
This testcase solves it.
"""

__author__ = "Max Syabro"
__email__ = "maxim@syabro.com"
__url__ = "__contact__"

from django.db import connections, DEFAULT_DB_ALIAS
from django.db.migrations.loader import MigrationLoader
from django.test import TestCase, override_settings


class MigrationsConflictsTestCase(TestCase):

    @override_settings(MIGRATION_MODULES={})
    def test_conflicts(self):
        loader = MigrationLoader(connections[DEFAULT_DB_ALIAS])
        conflicts = loader.detect_conflicts()
        if conflicts:
            name_str = "; ".join(
                "%s in %s" % (", ".join(names), app)
                for app, names in conflicts.items()
            )
            raise Exception(
                "Conflicting migrations detected (%s).\nTo fix them run "
                "'python manage.py makemigrations --merge'" % name_str
            )