Django单元测试不执行原始模型中的django信号

# settings.py
SIGNALS = True

from django.db.models.signals import post_save
from django.dispatch import receiver

@receiver(post_save, sender=MyModel)
def my_signal_handler(sender, instance, **kwargs):
    # 信号处理逻辑
    pass

from django.test import TestCase
from myapp.models import MyModel

class MyModelTestCase(TestCase):
    def test_signal_execution(self):
        # 创建模型实例并保存
        my_model = MyModel.objects.create(name='example')
        my_model.save()

        # 断言信号处理逻辑是否执行
        # ...