Python 如何测试FastAPI路由中是否使用了模型？_Python_Unit Testing_Pytest_Python Unittest_Fastapi

Python 如何测试FastAPI路由中是否使用了模型？

python unit-testing

Python 如何测试FastAPI路由中是否使用了模型？,python,unit-testing,pytest,python-unittest,fastapi,Python,Unit Testing,Pytest,Python Unittest,Fastapi,我试图检查是否有一个特定的模型被用作FastAPI路由的输入解析器。然而，我不知道如何修补（或监视）它我有以下文件结构： . └── roo ├── __init__.py ├── main.py └── test_demo.py main.py： from fastapi import FastAPI from pydantic import BaseModel app = FastAPI() class ItemModel(BaseModel): na

我试图检查是否有一个特定的模型被用作FastAPI路由的输入解析器。然而，我不知道如何修补（或监视）它

我有以下文件结构：

.
└── roo
    ├── __init__.py
    ├── main.py
    └── test_demo.py

main.py：

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()

class ItemModel(BaseModel):
    name: str

@app.post("/")
async def read_main(item: ItemModel):
    return {"msg": f"Item: {item.name}"}

test_demo.py：

from fastapi.testclient import TestClient
from unittest.mock import patch
from roo.main import app, ItemModel

client = TestClient(app)

def test_can_creating_new_item_users_proper_validation_model():
    with patch('roo.main.ItemModel', wraps=ItemModel) as patched_model:
        response = client.post("/", json={'name': 'good'})
    assert response.status_code == 200
    assert response.json() == {"msg": "Item: good"}
    assert patched_model.called

但是，

patched_model

从未被调用（其他断言通过）。我不想更改main.py中的功能或替换

ItemModel

，我只想检查它是否被使用。

我的第一个方法是包装

read\u main

方法，并检查传递到函数中的

项是否确实是ItemModel
的实例。但这是一个死胡同，因为FastAPI端点的准备和存储方式：FastAPI将端点函数对象的副本存储在列表中：（请参阅），然后在请求时计算要调用的端点
来自roo.main导入应用程序
def test_read_main（）：
在[r.endpoint.\u name\uuuuuuuu]中为r-in-app.routes断言'read\u main'
#检查read_main是否被调用*并*接收到ItemModel实例？

我的第二种方法涉及监视或“破坏”ItemModel
的初始化，这样，如果端点确实使用该模型，那么“破坏”的ItemModel
将导致命中该端点的请求失败。我们“中断”ItemModel
，方法是利用以下事实：（1）FastAPI在请求-响应周期内调用模型的\uuuu init\uuuu
，以及（2）当端点无法正确序列化模型时，默认情况下传播422错误响应：
class ItemModel（基本模型）：
姓名：str
def uuu init uuu（uuu pydantic_self，**数据：任意）->无：
打印（“提出POST请求并确认已打印”）
超级（）

因此，在测试中，只需模拟\uuuu init\uuu
方法：

pytest示例
import pytest
from fastapi.testclient import TestClient
from roo.main import app, ItemModel

def test_read_main(monkeypatch: pytest.MonkeyPatch):
    client = TestClient(app)

    def broken_init(self, **data):
        pass  # `name` and other fields won't be set

    monkeypatch.setattr(ItemModel, '__init__', broken_init)
    with pytest.raises(AttributeError) as exc:
        client.post("/", json={'name': 'good'})
        assert 422 == response.status_code
    assert "'ItemModel' object has no attribute" in str(exc.value)

def test_read_main(monkeypatch: pytest.MonkeyPatch):
    client = TestClient(app)

    def broken_init(self, **data):
        pass

    # Are we really using ItemModel?
    monkeypatch.setattr(ItemModel, '__init__', broken_init)
    with pytest.raises(AttributeError) as exc:
        response = client.post("/", json={'name': 'good'})
        assert 422 == response.status_code
    assert "'ItemModel' object has no attribute" in str(exc.value)

    # Okay, really using ItemModel. Does it work correctly?
    monkeypatch.undo()
    response = client.post("/", json={'name': 'good'})
    assert response.status_code == 200
    assert response.json() == {"msg": "Item: good"}


pytest+的示例
import pytest
from fastapi.testclient import TestClient
from roo.main import app, ItemModel

def test_read_main(monkeypatch: pytest.MonkeyPatch):
    client = TestClient(app)

    def broken_init(self, **data):
        pass  # `name` and other fields won't be set

    monkeypatch.setattr(ItemModel, '__init__', broken_init)
    with pytest.raises(AttributeError) as exc:
        client.post("/", json={'name': 'good'})
        assert 422 == response.status_code
    assert "'ItemModel' object has no attribute" in str(exc.value)

def test_read_main(monkeypatch: pytest.MonkeyPatch):
    client = TestClient(app)

    def broken_init(self, **data):
        pass

    # Are we really using ItemModel?
    monkeypatch.setattr(ItemModel, '__init__', broken_init)
    with pytest.raises(AttributeError) as exc:
        response = client.post("/", json={'name': 'good'})
        assert 422 == response.status_code
    assert "'ItemModel' object has no attribute" in str(exc.value)

    # Okay, really using ItemModel. Does it work correctly?
    monkeypatch.undo()
    response = client.post("/", json={'name': 'good'})
    assert response.status_code == 200
    assert response.json() == {"msg": "Item: good"}


单元测试示例
from fastapi.testclient import TestClient
from roo.main import app, ItemModel
from unittest.mock import patch

def test_read_main():
    client = TestClient(app)

    # Wrapping __init__ like this isn't really correct, but serves the purpose
    with patch.object(ItemModel, '__init__', wraps=ItemModel.__init__) as mocked_init:
        response = client.post("/", json={'name': 'good'})
        assert 422 == response.status_code
        mocked_init.assert_called()
        mocked_init.assert_called_with(**{'name': 'good'})

def test_read_main():
    client = TestClient(app)

    # Are we really using ItemModel?
    with patch.object(ItemModel, '__init__', wraps=ItemModel.__init__) as mocked_init:
        response = client.post("/", json={'name': 'good'})
        assert 422 == response.status_code
        mocked_init.assert_called()
        mocked_init.assert_called_with(**{'name': 'good'})

    # Okay, really using ItemModel. Does it work correctly?
    response = client.post("/", json={'name': 'good'})
    assert response.status_code == 200
    assert response.json() == {"msg": "Item: good"}



同样，测试检查端点在序列化为ItemModel
或访问item.name
时是否失败，这仅在端点确实使用ItemModel
时才会发生
如果将端点从item:ItemModel
修改为item:OtherModel
：
class OtherModel(BaseModel):
    name: str

class ItemModel(BaseModel):
    name: str

@app.post("/")
async def read_main(item: OtherModel):  # <----
    return {"msg": f"Item: {item.name}"}

422==200的断言错误有点令人困惑，但它基本上意味着，即使我们“破坏了”ItemModel
，我们仍然得到了200/OK响应。。这意味着未使用ItemModel

同样，如果您首先修改了测试，并模拟了OtherModel'的\uuu init\uuu
，而不是
ItemModel`，那么在不修改端点的情况下运行测试将导致类似的失败测试：
def test_read_main（mocker:mockerfix）：
client=TestClient（应用程序）
spy=mocker.spy（其他模型，'.\u init'）
client.post（“/”，json={'name'：'good'}）
>spy.assert_调用（）
E AssertionError:预期已调用“\uuuu init\uuuuuuu”。
def test_read_main（）：
client=TestClient（应用程序）
将patch.object（OtherModel，'.'uuuu init'.'uuuuu'，wrapps=OtherModel.'uuuuuu init.'uuuuuuuuu'）作为mock_init：
response=client.post（“/”，json={'name'：'good'}）
#assert 422==response.status\u代码
>mocked_init.assert_called（）
E AssertionError:预期已调用“\uuuu init\uuuuuuu”。

这里的断言不那么令人费解，因为它说我们期望端点调用OtherModel
的\uuuu init\uuuu
，但它没有被调用。它应该在修改端点以使用项：OtherModel
后通过
最后要注意的一点是，由于我们正在操作\uuuu init\uuuu
，因此它可能会导致“快乐路径”失败，因此现在应该单独测试它。确保撤消/恢复模拟和修补程序：

pytest示例
import pytest
from fastapi.testclient import TestClient
from roo.main import app, ItemModel

def test_read_main(monkeypatch: pytest.MonkeyPatch):
    client = TestClient(app)

    def broken_init(self, **data):
        pass  # `name` and other fields won't be set

    monkeypatch.setattr(ItemModel, '__init__', broken_init)
    with pytest.raises(AttributeError) as exc:
        client.post("/", json={'name': 'good'})
        assert 422 == response.status_code
    assert "'ItemModel' object has no attribute" in str(exc.value)

def test_read_main(monkeypatch: pytest.MonkeyPatch):
    client = TestClient(app)

    def broken_init(self, **data):
        pass

    # Are we really using ItemModel?
    monkeypatch.setattr(ItemModel, '__init__', broken_init)
    with pytest.raises(AttributeError) as exc:
        response = client.post("/", json={'name': 'good'})
        assert 422 == response.status_code
    assert "'ItemModel' object has no attribute" in str(exc.value)

    # Okay, really using ItemModel. Does it work correctly?
    monkeypatch.undo()
    response = client.post("/", json={'name': 'good'})
    assert response.status_code == 200
    assert response.json() == {"msg": "Item: good"}


pytest+的示例
import pytest
from fastapi.testclient import TestClient
from roo.main import app, ItemModel

def test_read_main(monkeypatch: pytest.MonkeyPatch):
    client = TestClient(app)

    def broken_init(self, **data):
        pass  # `name` and other fields won't be set

    monkeypatch.setattr(ItemModel, '__init__', broken_init)
    with pytest.raises(AttributeError) as exc:
        client.post("/", json={'name': 'good'})
        assert 422 == response.status_code
    assert "'ItemModel' object has no attribute" in str(exc.value)

def test_read_main(monkeypatch: pytest.MonkeyPatch):
    client = TestClient(app)

    def broken_init(self, **data):
        pass

    # Are we really using ItemModel?
    monkeypatch.setattr(ItemModel, '__init__', broken_init)
    with pytest.raises(AttributeError) as exc:
        response = client.post("/", json={'name': 'good'})
        assert 422 == response.status_code
    assert "'ItemModel' object has no attribute" in str(exc.value)

    # Okay, really using ItemModel. Does it work correctly?
    monkeypatch.undo()
    response = client.post("/", json={'name': 'good'})
    assert response.status_code == 200
    assert response.json() == {"msg": "Item: good"}


单元测试示例
from fastapi.testclient import TestClient
from roo.main import app, ItemModel
from unittest.mock import patch

def test_read_main():
    client = TestClient(app)

    # Wrapping __init__ like this isn't really correct, but serves the purpose
    with patch.object(ItemModel, '__init__', wraps=ItemModel.__init__) as mocked_init:
        response = client.post("/", json={'name': 'good'})
        assert 422 == response.status_code
        mocked_init.assert_called()
        mocked_init.assert_called_with(**{'name': 'good'})

def test_read_main():
    client = TestClient(app)

    # Are we really using ItemModel?
    with patch.object(ItemModel, '__init__', wraps=ItemModel.__init__) as mocked_init:
        response = client.post("/", json={'name': 'good'})
        assert 422 == response.status_code
        mocked_init.assert_called()
        mocked_init.assert_called_with(**{'name': 'good'})

    # Okay, really using ItemModel. Does it work correctly?
    response = client.post("/", json={'name': 'good'})
    assert response.status_code == 200
    assert response.json() == {"msg": "Item: good"}



总而言之，您可能想考虑是否/为什么检查正确使用哪个模型是有用的。通常，我只检查传入的有效请求参数是否返回预期的有效响应，同样，无效请求是否返回错误响应