code: 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-header/{item_id}": {
                  "get": {
                      "responses": {
                          "200": {
                              "description": "Successful Response",
                              "content": {
                                  "application/json": {"schema": {}}
                              },
                          },
                          "422": {
                              "description": "Validation Error",
                              "content": {
                                  "application/json": {
                                      "schema": {
                                          "$ref": "#/components/schemas/HTTPValidationError"
                                      }
                                  }
                              },
                          },
                      },
                      "summary": "Read Item Header",
                      "operationId": "read_item_header_items_header__item_id__get",
                      "parameters": [
                          {
                              "required": True,
                              "schema": {
                                  "title": "Item Id",
                                  "type": "string",
                              },
                              "name": "item_id",
                              "in": "path",
                          }
                      ],
                  }
              }
          },
          "components": {
              "schemas": {
                  "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"
                              },
                          }
                      },
                  },
              }
          },
      }
  
imports: from fastapi.testclient import TestClient
  from docs_src.handling_errors.tutorial002 import app
label_desc: Use image node_id 3 for calling a global function with example usage: test_openapi_schema() without return types