from typing import Union from fastapi import FastAPI, Form from fastapi.testclient import TestClient from pydantic import BaseModel from typing_extensions import Annotated app = FastAPI() class UserForm(BaseModel): name: str email: str class CompanyForm(BaseModel): company_name: str industry: str @app.post("/form-union/") def post_union_form(data: Annotated[Union[UserForm, CompanyForm], Form()]): return {"received": data} client = TestClient(app) def test_post_user_form(): response = client.post( "/form-union/", data={"name": "John Doe", "email": "john@example.com"} ) assert response.status_code == 200, response.text assert response.json() == { "received": {"name": "John Doe", "email": "john@example.com"} } def test_post_company_form(): response = client.post( "/form-union/", data={"company_name": "Tech Corp", "industry": "Technology"} ) assert response.status_code == 200, response.text assert response.json() == { "received": {"company_name": "Tech Corp", "industry": "Technology"} } def test_invalid_form_data(): response = client.post( "/form-union/", data={"name": "John", "company_name": "Tech Corp"}, ) assert response.status_code == 422, response.text def test_empty_form(): response = client.post("/form-union/") assert response.status_code == 422, response.text 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": { "/form-union/": { "post": { "summary": "Post Union Form", "operationId": "post_union_form_form_union__post", "requestBody": { "content": { "application/x-www-form-urlencoded": { "schema": { "anyOf": [ {"$ref": "#/components/schemas/UserForm"}, {"$ref": "#/components/schemas/CompanyForm"}, ], "title": "Data", } } }, "required": True, }, "responses": { "200": { "description": "Successful Response", "content": {"application/json": {"schema": {}}}, }, "422": { "description": "Validation Error", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/HTTPValidationError" } } }, }, }, } } }, "components": { "schemas": { "CompanyForm": { "properties": { "company_name": {"type": "string", "title": "Company Name"}, "industry": {"type": "string", "title": "Industry"}, }, "type": "object", "required": ["company_name", "industry"], "title": "CompanyForm", }, "HTTPValidationError": { "properties": { "detail": { "items": {"$ref": "#/components/schemas/ValidationError"}, "type": "array", "title": "Detail", } }, "type": "object", "title": "HTTPValidationError", }, "UserForm": { "properties": { "name": {"type": "string", "title": "Name"}, "email": {"type": "string", "title": "Email"}, }, "type": "object", "required": ["name", "email"], "title": "UserForm", }, "ValidationError": { "properties": { "loc": { "items": { "anyOf": [{"type": "string"}, {"type": "integer"}] }, "type": "array", "title": "Location", }, "msg": {"type": "string", "title": "Message"}, "type": {"type": "string", "title": "Error Type"}, }, "type": "object", "required": ["loc", "msg", "type"], "title": "ValidationError", }, } }, }