在烧瓶中测试 409 冲突答案

【问题标题】：Testing 409 conflict in flask-potion在烧瓶中测试 409 冲突
【发布时间】：2016-08-18 18:42:26
【问题描述】：

如果存在具有相同 id 的模型资源，我正在尝试测试烧瓶药水的模型资源是否在创建时发生冲突：

class Device(db.Model):
    __tablename__ = 'device'
    uuid = db.Column(UUID, primary_key=True, default=lambda: str(uuid4()))
    make = db.Column(db.String(150), nullable=False)
    model = db.Column(db.String(150), nullable=False)
    category = db.Column(db.String(150), nullable=False)

class DeviceResource(ModelResource):
    class Meta:
        model = Device
        id_converter = 'string'

    class Schema:
        uuid = fields.UUID(io='wr')

并且测试是作为 pytest yield 夹具完成的：

@pytest.fixture(scope='session')
def application():
    flask_app = create_app()
    # return a webtest.TestApp
    test_app = TestApp(flask_app)
    test_app.current_app_context = flask_app.app_context
    return test_app

@pytest.yield_fixture(scope='function')
def single_device(application):
    obj = Device(**DEVICE_JSON)
    with application.current_app_context():
        db.session.add(obj)
        db.session.commit()
        yield obj
        for device in Device.query.all():
            db.session.delete(device)
        db.session.commit()

def test_create_device_fail(single_device, application):
     response = application.post_json('/api/v1/device', params=DEVICE_JSON, expect_errors=True)
     assert response.status_code == 409

但是当我运行时出现以下错误：

sqlalchemy.exc.InvalidRequestError: This Session's transaction has been rolled back due to a previous exception during flush. To begin a new transaction with this Session, first issue Session.rollback(). Original exception was: New instance <Device at 0x7fb5e83d5d68> with identity key (<class 'complex_service.db.Device'>, ('1ec67df1-e673-4505-8e00-5be58ec1656a',)) conflicts with persistent instance <Device at 0x7fb5e84419e8>

一起

sqlalchemy.orm.exc.FlushError: New instance <Device at 0x7fb5e83d5d68> with identity key (<class 'complex_service.db.Device'>, ('1ec67df1-e673-4505-8e00-5be58ec1656a',)) conflicts with persistent instance <Device at 0x7fb5e84419e8>

即使我没有通过测试中的夹具，而是执行了双重请求，它也不起作用，失败并出现相同的错误

def test_create_device_fail(single_device, application):
     application.post_json('/api/v1/device', params=DEVICE_JSON, expect_errors=True)
     assert response.status_code == 200
     response = application.post_json('/api/v1/device', params=DEVICE_JSON, expect_errors=True)
     assert response.status_code == 409

关于如何解决它的任何想法？

【问题讨论】：

不确定 pytest 究竟是如何工作的，但似乎在single_device() 添加设备，然后在yield 输入测试？您可能应该在屈服之前离开应用上下文，然后在测试后再次输入以删除设备。
像这样制作夹具：@pytest.yield_fixture(scope='function') def single_device(application): obj = Device(**DEVICE_JSON) with application.current_app_context(): db.session.add(obj) db.session.commit() yield obj with application.current_app_context(): for device in Device.query.all(): db.session.delete(device) db.session.commit() 我收到一个新错误：sqlalchemy.orm.exc.DetachedInstanceError: Instance <Device at 0x7fab4e154ef0> is not bound to a Session; attribute refresh operation cannot proceed

标签： python-3.x flask sqlalchemy pytest flask-potion

【解决方案1】：

感谢@lyschoening 的建议，我设法让它工作了，

@pytest.yield_fixture(scope='function')
def single_device(application):
    obj = Device(**DEVICE_JSON)
    with application.current_app_context():
        db.session.add(obj)
        db.session.commit()
    yield None
    with application.current_app_context():  
        for device in Device.query.all():
            db.session.delete(device)
        db.session.commit()

所以基本上不会让对象进行测试并具有 2 个不同的应用程序上下文

【讨论】：