FastAPI route works in Swagger but returns HTTP 422 in unit test-CodePudding

I have a FastAPI app that implements a route like so.

from fastapi import FastAPI

api = FastAPI()

@api.post("/myroute/")
def myroute(a: str, b: str) -> str:
    return f"a={a}, b={b}"

This works as expected when I run the server and use Swagger to interact with it.

I have the following unit test.

from fastapi.testclient import TestClient

def test_myroute():
    client = TestClient(api)
    response = client.post("/myroute/", json={"a": "dog", "b": "cat"})
    assert response.status_code == 200

The unit test fails with an HTTP 422 Unprocessable Entity.

Have I written the unit test incorrectly?

There is a similar StackOverflow question here, but there the solution is to use the json keyword in the unit test, which I am already doing.

CodePudding user response：

Here is a solution.

from fastapi import FastAPI
from pydantic import BaseModel

api = FastAPI()

class Arguments(BaseModel):
    a: str
    b: str

@api.post("/myroute/")
def myroute(arguments: Arguments) -> str:
    return f"a={arguments.a}, b={arguments.b}":

See the comment responding to the original post for an explanation.