Django relation "accounts_user" does not exist

my django project

Subject
    accounts
    courses
        views.py
        tests
            test_models.py
    subject

test_models.py:

from django.core.urlresolvers import reverse

from django.test import TestCase

from .models import MultiSubject
from accounts.models import User

class DjanoRestFrameworkTests(TestCase):

    def setUp(self):
        part=Part.objects.get(pk=2)
        MultiSubject.get_or_create(part=part, number=1, title="", description=":?")

    def test_MultiSubject(self):
        title = MultiSubject.get(title="")
        description = MultiSubject.get(description=":?")
        self.assertEqual(
            title.get_title, " : :?"
        )

run python manage.py test error
django.db.utils.ProgrammingError: relation "accounts_user" does not exist

both python manage.py makemigrations and python manage.py miagrate can execute normally
what is the reason