class Message(BaseModel):
    input: str
    output: MessageOutput


app = FastAPI(title="Minimal FastAPI App", version="1.0.0")


@app.post("/messages", response_model=Message)
async def create_message(input_message: str) -> Message:
    return Message(
        input=input_message,
        output=MessageOutput(body=f"Processed: {input_message}"),
    )


client = TestClient(app)