Pytest-django:设置用户权限

Question

我使用pytest 3.0.6和pytest-django 3.1.2为Django开发了一个库。我有一个非常简单的测试失败，我不明白会发生什么：

# test_mytest.py
import pytest
from django.contrib.auth.models import Permission
from django.contrib.contenttypes.models import ContentType


@pytest.mark.django_db
def test_user_has_perm(django_user_model):
    # Create a new user
    john_doe = django_user_model.objects.create_user('johndoe', email='jd@example.com', password='123456')

    # Get or create the permission to set on user
    user_ct = ContentType.objects.get(app_label='auth', model='user')
    p, _ = Permission.objects.get_or_create(content_type=user_ct, codename='delete_user', name="Can delete user")

    # User don't have the permission
    assert john_doe.has_perm(p) is False

    # Set permission to user
    john_doe.user_permissions.add(p)
    assert john_doe.has_perm(p) is True  # ---> FAIL

以防万一，测试结果是：

$ pytest
============================= test session starts =============================
platform win32 -- Python 3.5.3, pytest-3.0.6, py-1.4.32, pluggy-0.4.0
Django settings: testsite.settings (from ini file)
rootdir: D:\Dev\foss\django-modern-rpc, inifile: tox.ini
plugins: pythonpath-0.7.1, django-3.1.2, cov-2.4.0
collected 1 items

modernrpc\tests\test_test_test.py F

================================== FAILURES ===================================
_____________________________ test_user_has_perm ______________________________

django_user_model = <class 'django.contrib.auth.models.User'>

    @pytest.mark.django_db
    def test_user_has_perm(django_user_model):
        # Create a new user
        john_doe = django_user_model.objects.create_user('johndoe', email='jd@example.com', password='123456')

        # Get or create the permission to set on user
        user_ct = ContentType.objects.get(app_label='auth', model='user')
        p, _ = Permission.objects.get_or_create(content_type=user_ct, codename='delete_user', name="Can delete user")

        # User don't have the permission
        assert john_doe.has_perm(p) is False

        # Set permission to user
        john_doe.user_permissions.add(p)
>       assert john_doe.has_perm(p) is True  # ---> FAIL
E       assert False is True
E        +  where False = <bound method PermissionsMixin.has_perm of <User: johndoe>>(<Permission: auth | user | Can delete user>)
E        +    where <bound method PermissionsMixin.has_perm of <User: johndoe>> = <User: johndoe>.has_perm

modernrpc\tests\test_test_test.py:20: AssertionError
========================== 1 failed in 0.32 seconds ===========================

配置块，来自tox.ini：

[pytest]
DJANGO_SETTINGS_MODULE = testsite.settings
norecursedirs = .git __pycache__ build dist venv* .tox .vscode .cache *.egg-info
python_paths = modernrpc/tests
testpaths = modernrpc/tests
python_files = test_*.py dummy_*.py

以及来自测试设置的DB配置：

BASE_DIR = os.path.dirname(os.path.dirname(__file__))
DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': os.path.join(BASE_DIR, 'modern_rpc.sqlite3'),
    },
}

我做错什么了？

Answer 1

您需要使用字符串'app_label.codename'

如果用户具有指定的权限，则返回True，其中perm格式为“”。

此外，如果自上次调用user._perm_cache或从数据库检索该用户的新实例以来更改了权限，则必须清除user._user_perm_cache和has_perm，以确保没有缓存：

 del john_doe._perm_cache
 del john_doe._user_perm_cache 
 # OR
 john_doe = django_user_model.objects.get(username='johndoe')

这是因为has_perm将调用auth后端，后者将首先查询这些缓存。

Answer 2

来自文档

has_perm(perm，obj=None) 如果用户具有指定的权限，则返回True，其中perm为格式 "<app label>.<permission codename>"。 (请参阅权限文档)。如果用户不活动，此方法将始终返回False。 如果传入obj，此方法将不检查模型的权限，而是检查此特定对象的权限。

因此，此方法接受字符串而不是权限对象。

john_doe.has_perm('auth.delete_user')

应该返回True。( delete_user权限分配了auth应用程序，因为您使用了user_ct来创建它，user_ct的应用程序就是auth)。

但是，在您的示例中，这种情况不会立即发生，因为也有一个权限检查缓存。

在您重新获取对象之后，它将工作。

#Be aware this only works after Django 1.9+
#https://code.djangoproject.com/ticket/26514
john_doe.refresh_from_db()
#Otherwise use:
john_doe = User.objects.get(pk=john_doe.pk)