Testing for pending migrations in Django

# The MIT License (MIT)
#
# Copyright (c) 2016 Damien Lespiau
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import sys
from cStringIO import StringIO
from contextlib import contextmanager

from django.core import management
from django.test import TestCase


@contextmanager
def capture(command, *args, **kwargs):
    out, sys.stdout = sys.stdout, StringIO()
    command(*args, **kwargs)
    sys.stdout.seek(0)
    yield sys.stdout.read()
    sys.stdout = out


def makemigrations():
    management.call_command('makemigrations')


class MigrationTest(TestCase):

    def testPendingMigration(self):
        """Make sure there's no pending migration."""

        with capture(makemigrations) as output:
            self.assertEqual(output, "No changes detected\n")