{
  "id": "python/unittest-setupclass-error",
  "signature": "TypeError: setUpClass() missing 1 required positional argument: 'cls'",
  "signature_zh": "类型错误：setUpClass()缺少一个必需的位置参数：'cls'",
  "regex": "TypeError:\\ setUpClass\\(\\)\\ missing\\ 1\\ required\\ positional\\ argument:\\ 'cls'",
  "domain": "python",
  "category": "type_error",
  "subcategory": null,
  "root_cause": "在unittest中，setUpClass方法定义错误，没有使用@classmethod装饰器或缺少cls参数。",
  "root_cause_type": "generic",
  "root_cause_zh": "setUpClass未正确声明为类方法，导致缺少cls参数。",
  "versions": [
    {
      "version": "3.10",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "",
      "why_fails": "无法进行类级别的初始化。",
      "fail_rate": 0.9,
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "why_fails": "setUp在每个测试前执行，不符合类级别需求。",
      "fail_rate": 0.8,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "",
      "success_rate": 1.0,
      "how": "@classmethod\ndef setUpClass(cls):\n    super().setUpClass()",
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "success_rate": 0.9,
      "how": "@pytest.fixture(scope='class')\ndef setup_class():\n    pass",
      "condition": "",
      "sources": []
    }
  ],
  "workarounds_zh": [],
  "transition_graph": {
    "leads_to": [],
    "preceded_by": [],
    "frequently_confused_with": []
  },
  "official_doc_url": null,
  "official_doc_section": null,
  "error_code": null,
  "verification_tier": "ai_generated",
  "confidence": 0.84,
  "fix_success_rate": 0.8,
  "resolvable": "true",
  "first_seen": "2025-08-02",
  "last_confirmed": "2025-01-01",
  "last_updated": "2025-01-01",
  "evidence_count": 0,
  "tags": [],
  "locale": "en",
  "aliases": []
}