python-使用pytest测试django应用程序时出错，没有安装带有此标签的应用程序

我正在用pytest为django应用程序实现测试。我添加了decorator@pytest。做记号django_db访问我的test_函数，这样我就可以访问我的数据库（sqlite3）。当我运行一个简单的断言响应时。状态代码发生错误，告诉我没有安装带有标签的应用程序。我希望我的应用程序出现在已安装的应用程序设置中。

完整的错误消息：

(env) Inspiron-3793:~/Python-OC-Lettings-FR$ pytest lettings/
============================================================== test session starts ===============================================================
platform linux -- Python 3.9.7, pytest-7.1.1, pluggy-1.0.0 -- /home/arthur/openclass/P13/Python-OC-Lettings-FR/env/bin/python3
cachedir: .pytest_cache
django: settings: oc_lettings_site.settings (from ini)
rootdir: /home/arthur/openclass/P13/Python-OC-Lettings-FR, configfile: setup.cfg
plugins: django-3.9.0, mock-3.7.0
collected 1 item                                                                                                                                 

lettings/tests/unit/tests.py::TestLettings::test_index ERROR                                                                               [100%]

===================================================================== ERRORS =====================================================================
___________________________________________________ ERROR at setup of TestLettings.test_index ____________________________________________________

self = , app_label = 'oc_lettings_site'

    def get_app_config(self, app_label):
        """
        Import applications and returns an app config for the given label.
    
        Raise LookupError if no application exists with this label.
        """
        self.check_apps_ready()
        try:
>           return self.app_configs[app_label]
E           KeyError: 'oc_lettings_site'

env/lib/python3.9/site-packages/django/apps/registry.py:155: KeyError

During handling of the above exception, another exception occurred:

request = >

    @pytest.fixture(autouse=True)
    def _django_db_marker(request):
        """Implement the django_db marker, internal to pytest-django.
    
        This will dynamically request the ``db``, ``transactional_db`` or
        ``django_db_reset_sequences`` fixtures as required by the django_db marker.
        """
        marker = request.node.get_closest_marker("django_db")
        if marker:
            transaction, reset_sequences = validate_django_db(marker)
            if reset_sequences:
                request.getfixturevalue("django_db_reset_sequences")
            elif transaction:
                request.getfixturevalue("transactional_db")
            else:
>               request.getfixturevalue("db")

env/lib/python3.9/site-packages/pytest_django/plugin.py:513: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
env/lib/python3.9/site-packages/pytest_django/fixtures.py:105: in django_db_setup
    db_cfg = setup_databases(
env/lib/python3.9/site-packages/django/test/utils.py:169: in setup_databases
    connection.creation.create_test_db(
env/lib/python3.9/site-packages/django/db/backends/base/creation.py:67: in create_test_db
    call_command(
env/lib/python3.9/site-packages/django/core/management/__init__.py:168: in call_command
    return command.execute(*args, **defaults)
env/lib/python3.9/site-packages/django/core/management/base.py:369: in execute
    output = self.handle(*args, **options)
env/lib/python3.9/site-packages/django/core/management/base.py:83: in wrapped
    res = handle_func(*args, **kwargs)
env/lib/python3.9/site-packages/django/core/management/commands/migrate.py:231: in handle
    post_migrate_state = executor.migrate(
env/lib/python3.9/site-packages/django/db/migrations/executor.py:117: in migrate
    state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
env/lib/python3.9/site-packages/django/db/migrations/executor.py:147: in _migrate_all_forwards
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
env/lib/python3.9/site-packages/django/db/migrations/executor.py:245: in apply_migration
    state = migration.apply(state, schema_editor)
env/lib/python3.9/site-packages/django/db/migrations/migration.py:124: in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
env/lib/python3.9/site-packages/django/db/migrations/operations/special.py:190: in database_forwards
    self.code(from_state.apps, schema_editor)
lettings/migrations/0002_auto_20220406_1825.py:13: in fill_address
    Old_address = apps.get_model("oc_lettings_site", "address")
env/lib/python3.9/site-packages/django/apps/registry.py:205: in get_model
    app_config = self.get_app_config(app_label)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = , app_label = 'oc_lettings_site'

    def get_app_config(self, app_label):
        """
        Import applications and returns an app config for the given label.
    
        Raise LookupError if no application exists with this label.
        """
        self.check_apps_ready()
        try:
            return self.app_configs[app_label]
        except KeyError:
            message = "No installed app with label '%s'." % app_label
            for app_config in self.get_app_configs():
                if app_config.name == app_label:
                    message += " Did you mean '%s'?" % app_config.label
                    break
>           raise LookupError(message)
E           LookupError: No installed app with label 'oc_lettings_site'.

env/lib/python3.9/site-packages/django/apps/registry.py:162: LookupError
------------------------------------------------------------- Captured stderr setup --------------------------------------------------------------
Creating test database for alias 'default'...
============================================================ short test summary info =============================================================
ERROR lettings/tests/unit/tests.py::TestLettings::test_index - LookupError: No installed app with label 'oc_lettings_site'.
================================================================ 1 error in 0.23s ================================================================

测试：

import pytest
from django.urls import reverse


@pytest.mark.django_db
class TestLettings:
    '''This is the testclass for index_view'''

    def test_index(self, client):
        '''This test ...'''
        response = client.get(reverse('lettings:index'))
        assert response.status_code == 200