Client.login メソッドを使ってログインする
from django.test import Client, TestCase
class HogeTestCase(TestCase):
"""
"""
def setUp(self):
"""
"""
self.user = User.objects.create_user('HogeTaro', 'taro@hoge.com', 'password')
self.client = Client()
self.client.login(username='HogeTaro', password='password')