code: def test_init_fail_wo_api_key(self, monkeypatch):
      monkeypatch.delenv("OPENAI_API_KEY", raising=False)
      with pytest.raises(OpenAIError):
          OpenAIChatGenerator()
  
imports: import os
  import pytest
  from openai import OpenAIError
  from haystack.components.generators.chat import OpenAIChatGenerator
  from haystack.components.generators.utils import default_streaming_callback
  from haystack.dataclasses import ChatMessage, StreamingChunk
label_desc: Use image node_id 2 for calling the TestOpenAIChatGenerator obj's underlying member method code with example usage: obj.test_init_fail_wo_api_key(monkeypatch) without return types