from typing import Optional, Union from fastapi import FastAPI from pydantic import BaseModel from starlette.testclient import TestClient app = FastAPI() class Item(BaseModel): name: Optional[str] = None class OtherItem(BaseModel): price: int @app.post("/items/") def save_union_body(item: Union[OtherItem, Item]): return {"item": item} client = TestClient(app) item_openapi_schema = { "openapi": "3.0.2", "info": {"title": "Fast API", "version": "0.1.0"}, "paths": { "/items/": { "post": { "responses": { "200": { "description": "Successful Response", "content": {"application/json": {"schema": {}}}, }, "422": { "description": "Validation Error", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/HTTPValidationError" } } }, }, }, "summary": "Save Union Body", "operationId": "save_union_body_items__post", "requestBody": { "content": { "application/json": { "schema": { "title": "Item", "anyOf": [ {"$ref": "#/components/schemas/OtherItem"}, {"$ref": "#/components/schemas/Item"}, ], } } }, "required": True, }, } } }, "components": { "schemas": { "OtherItem": { "title": "OtherItem", "required": ["price"], "type": "object", "properties": {"price": {"title": "Price", "type": "integer"}}, }, "Item": { "title": "Item", "type": "object", "properties": {"name": {"title": "Name", "type": "string"}}, }, "ValidationError": { "title": "ValidationError", "required": ["loc", "msg", "type"], "type": "object", "properties": { "loc": { "title": "Location", "type": "array", "items": {"type": "string"}, }, "msg": {"title": "Message", "type": "string"}, "type": {"title": "Error Type", "type": "string"}, }, }, "HTTPValidationError": { "title": "HTTPValidationError", "type": "object", "properties": { "detail": { "title": "Detail", "type": "array", "items": {"$ref": "#/components/schemas/ValidationError"}, } }, }, } }, } def test_item_openapi_schema(): response = client.get("/openapi.json") assert response.status_code == 200 assert response.json() == item_openapi_schema def test_post_other_item(): response = client.post("/items/", json={"price": 100}) assert response.status_code == 200 assert response.json() == {"item": {"price": 100}} def test_post_item(): response = client.post("/items/", json={"name": "Foo"}) assert response.status_code == 200 assert response.json() == {"item": {"name": "Foo"}}