使用覆寫測試依賴項¶
在測試期間覆寫依賴項¶
在某些情況下，您可能需要在測試期間覆寫依賴項。
您不希望執行原始依賴項（及其任何子依賴項）。
相反，您希望提供僅在測試期間（可能僅在某些特定測試中）使用的不同依賴項，並提供可在使用原始依賴項值的地方使用的值。
使用案例：外部服務¶
例如，您可能需要呼叫外部驗證提供者。
您向其發送一個權杖，它會返回一個已驗證的使用者。
此提供者可能會根據每次請求向您收費，並且呼叫它可能比使用固定的模擬測試使用者需要更多時間。
您可能想要測試一次外部提供者，但不一定在每次測試執行時都呼叫它。
在這種情況下，您可以覆寫呼叫該提供者的依賴項，並使用僅針對您的測試返回模擬使用者的自訂依賴項。
使用 app.dependency_overrides 屬性¶
針對這些情況，您的 FastAPI 應用程式有一個屬性 app.dependency_overrides，它是一個簡單的 dict（字典）。
要覆寫測試的依賴項，您可以將原始依賴項（一個函式）作為鍵，並將您的依賴項覆寫（另一個函式）作為值。
然後 FastAPI 將呼叫該覆寫而不是原始依賴項。
from typing import Annotated
from fastapi import Depends, FastAPI
from fastapi.testclient import TestClient
app = FastAPI()
async def common_parameters(q: str | None = None, skip: int = 0, limit: int = 100):
return {"q": q, "skip": skip, "limit": limit}
@app.get("/items/")
async def read_items(commons: Annotated[dict, Depends(common_parameters)]):
return {"message": "Hello Items!", "params": commons}
@app.get("/users/")
async def read_users(commons: Annotated[dict, Depends(common_parameters)]):
return {"message": "Hello Users!", "params": commons}
client = TestClient(app)
async def override_dependency(q: str | None = None):
return {"q": q, "skip": 5, "limit": 10}
app.dependency_overrides[common_parameters] = override_dependency
def test_override_in_items():
response = client.get("/items/")
assert response.status_code == 200
assert response.json() == {
"message": "Hello Items!",
"params": {"q": None, "skip": 5, "limit": 10},
}
def test_override_in_items_with_q():
response = client.get("/items/?q=foo")
assert response.status_code == 200
assert response.json() == {
"message": "Hello Items!",
"params": {"q": "foo", "skip": 5, "limit": 10},
}
def test_override_in_items_with_params():
response = client.get("/items/?q=foo&skip=100&limit=200")
assert response.status_code == 200
assert response.json() == {
"message": "Hello Items!",
"params": {"q": "foo", "skip": 5, "limit": 10},
}
from typing import Annotated, Union
from fastapi import Depends, FastAPI
from fastapi.testclient import TestClient
app = FastAPI()
async def common_parameters(
q: Union[str, None] = None, skip: int = 0, limit: int = 100
):
return {"q": q, "skip": skip, "limit": limit}
@app.get("/items/")
async def read_items(commons: Annotated[dict, Depends(common_parameters)]):
return {"message": "Hello Items!", "params": commons}
@app.get("/users/")
async def read_users(commons: Annotated[dict, Depends(common_parameters)]):
return {"message": "Hello Users!", "params": commons}
client = TestClient(app)
async def override_dependency(q: Union[str, None] = None):
return {"q": q, "skip": 5, "limit": 10}
app.dependency_overrides[common_parameters] = override_dependency
def test_override_in_items():
response = client.get("/items/")
assert response.status_code == 200
assert response.json() == {
"message": "Hello Items!",
"params": {"q": None, "skip": 5, "limit": 10},
}
def test_override_in_items_with_q():
response = client.get("/items/?q=foo")
assert response.status_code == 200
assert response.json() == {
"message": "Hello Items!",
"params": {"q": "foo", "skip": 5, "limit": 10},
}
def test_override_in_items_with_params():
response = client.get("/items/?q=foo&skip=100&limit=200")
assert response.status_code == 200
assert response.json() == {
"message": "Hello Items!",
"params": {"q": "foo", "skip": 5, "limit": 10},
}
from typing import Union
from fastapi import Depends, FastAPI
from fastapi.testclient import TestClient
from typing_extensions import Annotated
app = FastAPI()
async def common_parameters(
q: Union[str, None] = None, skip: int = 0, limit: int = 100
):
return {"q": q, "skip": skip, "limit": limit}
@app.get("/items/")
async def read_items(commons: Annotated[dict, Depends(common_parameters)]):
return {"message": "Hello Items!", "params": commons}
@app.get("/users/")
async def read_users(commons: Annotated[dict, Depends(common_parameters)]):
return {"message": "Hello Users!", "params": commons}
client = TestClient(app)
async def override_dependency(q: Union[str, None] = None):
return {"q": q, "skip": 5, "limit": 10}
app.dependency_overrides[common_parameters] = override_dependency
def test_override_in_items():
response = client.get("/items/")
assert response.status_code == 200
assert response.json() == {
"message": "Hello Items!",
"params": {"q": None, "skip": 5, "limit": 10},
}
def test_override_in_items_with_q():
response = client.get("/items/?q=foo")
assert response.status_code == 200
assert response.json() == {
"message": "Hello Items!",
"params": {"q": "foo", "skip": 5, "limit": 10},
}
def test_override_in_items_with_params():
response = client.get("/items/?q=foo&skip=100&limit=200")
assert response.status_code == 200
assert response.json() == {
"message": "Hello Items!",
"params": {"q": "foo", "skip": 5, "limit": 10},
}
提示
如果可能，建議使用 Annotated 版本。
from fastapi import Depends, FastAPI
from fastapi.testclient import TestClient
app = FastAPI()
async def common_parameters(q: str | None = None, skip: int = 0, limit: int = 100):
return {"q": q, "skip": skip, "limit": limit}
@app.get("/items/")
async def read_items(commons: dict = Depends(common_parameters)):
return {"message": "Hello Items!", "params": commons}
@app.get("/users/")
async def read_users(commons: dict = Depends(common_parameters)):
return {"message": "Hello Users!", "params": commons}
client = TestClient(app)
async def override_dependency(q: str | None = None):
return {"q": q, "skip": 5, "limit": 10}
app.dependency_overrides[common_parameters] = override_dependency
def test_override_in_items():
response = client.get("/items/")
assert response.status_code == 200
assert response.json() == {
"message": "Hello Items!",
"params": {"q": None, "skip": 5, "limit": 10},
}
def test_override_in_items_with_q():
response = client.get("/items/?q=foo")
assert response.status_code == 200
assert response.json() == {
"message": "Hello Items!",
"params": {"q": "foo", "skip": 5, "limit": 10},
}
def test_override_in_items_with_params():
response = client.get("/items/?q=foo&skip=100&limit=200")
assert response.status_code == 200
assert response.json() == {
"message": "Hello Items!",
"params": {"q": "foo", "skip": 5, "limit": 10},
}
提示
如果可能，建議使用 Annotated 版本。
from typing import Union
from fastapi import Depends, FastAPI
from fastapi.testclient import TestClient
app = FastAPI()
async def common_parameters(
q: Union[str, None] = None, skip: int = 0, limit: int = 100
):
return {"q": q, "skip": skip, "limit": limit}
@app.get("/items/")
async def read_items(commons: dict = Depends(common_parameters)):
return {"message": "Hello Items!", "params": commons}
@app.get("/users/")
async def read_users(commons: dict = Depends(common_parameters)):
return {"message": "Hello Users!", "params": commons}
client = TestClient(app)
async def override_dependency(q: Union[str, None] = None):
return {"q": q, "skip": 5, "limit": 10}
app.dependency_overrides[common_parameters] = override_dependency
def test_override_in_items():
response = client.get("/items/")
assert response.status_code == 200
assert response.json() == {
"message": "Hello Items!",
"params": {"q": None, "skip": 5, "limit": 10},
}
def test_override_in_items_with_q():
response = client.get("/items/?q=foo")
assert response.status_code == 200
assert response.json() == {
"message": "Hello Items!",
"params": {"q": "foo", "skip": 5, "limit": 10},
}
def test_override_in_items_with_params():
response = client.get("/items/?q=foo&skip=100&limit=200")
assert response.status_code == 200
assert response.json() == {
"message": "Hello Items!",
"params": {"q": "foo", "skip": 5, "limit": 10},
}
提示
您可以為 FastAPI 應用程式中任何位置使用的依賴項設定覆寫。
原始依賴項可以用於路徑操作函式、路徑操作裝飾器（當您不使用返回值時）、.include_router() 呼叫等。
FastAPI 仍然能夠覆寫它。
然後，您可以透過將 app.dependency_overrides 設定為空的 dict 來重設您的覆寫（移除它們）。
app.dependency_overrides = {}
提示
如果您只想在某些測試期間覆寫依賴項，您可以在測試開始時（在測試函式內）設定覆寫，並在測試結束時（在測試函式末尾）重設它。