from typing import Optional, Union from dirty_equals import IsDict from fastapi import FastAPI from fastapi.testclient import TestClient from pydantic import BaseModel app = FastAPI() class Item(BaseModel): name: Optional[str] = None class ExtendedItem(Item): age: int @app.post("/items/") def save_union_different_body(item: Union[ExtendedItem, Item]): return {"item": item} client = TestClient(app) def test_post_extended_item(): response = client.post("/items/", json={"name": "Foo", "age": 5}) assert response.status_code == 200, response.text assert response.json() == {"item": {"name": "Foo", "age": 5}} def test_post_item(): response = client.post("/items/", json={"name": "Foo"}) assert response.status_code == 200, response.text assert response.json() == {"item": {"name": "Foo"}} def test_openapi_schema(): response = client.get("/openapi.json") assert response.status_code == 200, response.text assert response.json() == { "openapi": "3.1.0", "info": {"title": "FastAPI", "version": "0.1.0"}, "paths": { "/items/": { "post": { "responses": { "200": { "description": "Successful Response", "content": {"application/json": {"schema": {}}}, }, "422": { "description": "Validation Error", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/HTTPValidationError" } } }, }, }, "summary": "Save Union Different Body", "operationId": "save_union_different_body_items__post", "requestBody": { "content": { "application/json": { "schema": { "title": "Item", "anyOf": [ {"$ref": "#/components/schemas/ExtendedItem"}, {"$ref": "#/components/schemas/Item"}, ], } } }, "required": True, }, } } }, "components": { "schemas": { "Item": { "title": "Item", "type": "object", "properties": { "name": IsDict( { "title": "Name", "anyOf": [{"type": "string"}, {"type": "null"}], } ) | IsDict( # TODO: remove when deprecating Pydantic v1 {"title": "Name", "type": "string"} ) }, }, "ExtendedItem": { "title": "ExtendedItem", "required": ["age"], "type": "object", "properties": { "name": IsDict( { "title": "Name", "anyOf": [{"type": "string"}, {"type": "null"}], } ) | IsDict( # TODO: remove when deprecating Pydantic v1 {"title": "Name", "type": "string"} ), "age": {"title": "Age", "type": "integer"}, }, }, "ValidationError": { "title": "ValidationError", "required": ["loc", "msg", "type"], "type": "object", "properties": { "loc": { "title": "Location", "type": "array", "items": { "anyOf": [{"type": "string"}, {"type": "integer"}] }, }, "msg": {"title": "Message", "type": "string"}, "type": {"title": "Error Type", "type": "string"}, }, }, "HTTPValidationError": { "title": "HTTPValidationError", "type": "object", "properties": { "detail": { "title": "Detail", "type": "array", "items": {"$ref": "#/components/schemas/ValidationError"}, } }, }, } }, }