code: def test_no_default_url(app: Flask, model_class: t.Any) -> None:
      del app.config["SQLALCHEMY_DATABASE_URI"]
      app.config["SQLALCHEMY_BINDS"] = {"a": "sqlite://"}
      db = SQLAlchemy(
          app, model_class=model_class, engine_options={"echo": True}
      )
      assert None not in db.engines
      assert "a" in db.engines
  
imports: from __future__ import annotations
  import os.path
  import typing
  import unittest.mock
  import pytest
  import sqlalchemy
  import sqlalchemy.pool
  from flask import Flask
  from flask_sqlalchemy import SQLAlchemy
label_desc: Use image node_id 8 for calling a global function with example usage: test_no_default_url(app, model_class) without return types