如何在Django中运行python manage.py测试时强制使用新数据库？

# settings.py

# 默认数据库配置
DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'production_db',
        'USER': 'username',
        'PASSWORD': 'password',
        'HOST': 'localhost',
        'PORT': '3306',
    }
}

# 测试数据库配置
DATABASES['test'] = {
    'ENGINE': 'django.db.backends.mysql',
    'NAME': 'test_db',
    'USER': 'username',
    'PASSWORD': 'password',
    'HOST': 'localhost',
    'PORT': '3306',
}

python manage.py test --rebuild

# tests.py

from django.test import TestCase

class MyTestCase(TestCase):
    def setUp(self):
        # 设置测试数据库
        self._old_db_name = settings.DATABASES['default']['NAME']
        settings.DATABASES['default']['NAME'] = 'test_db'

    def tearDown(self):
        # 恢复原始数据库
        settings.DATABASES['default']['NAME'] = self._old_db_name

    def test_something(self):
        # 测试代码
        pass