---
url: /docs/guide/usage/linter/rules/vitest/require-hook.md
---

### 作用

此规则会标记测试文件顶层或直接位于 `describe` 函数体内的任何表达式，*但不包括* 以下内容：

* `import` 语句
* `const` 变量
* `let` *声明*，以及初始化为 `null` 或 `undefined` 的赋值
* 类
* 类型
* 对标准 Jest 全局对象的调用

### 为什么这不好？

将初始化和清理代码放在 hooks 之外可能会导致不可预测的测试行为。在顶层运行的代码会在测试文件加载时执行，而不是在测试运行时执行，这可能会导致测试隔离问题，并使测试依赖于执行顺序。使用 `beforeEach`、`beforeAll`、`afterEach` 和 `afterAll` 等适当的 hooks 可确保初始化和清理代码在正确的时间运行，并保持测试隔离。

### 示例

以下是此规则的**错误**代码示例：

```javascript
import { database, isCity } from "../database";
import { Logger } from "../../../src/Logger";
import { loadCities } from "../api";

jest.mock("../api");

const initializeCityDatabase = () => {
  database.addCity("Vienna");
  database.addCity("San Juan");
  database.addCity("Wellington");
};

const clearCityDatabase = () => {
  database.clear();
};

initializeCityDatabase();

test("that persists cities", () => {
  expect(database.cities.length).toHaveLength(3);
});
test("city database has Vienna", () => {
  expect(isCity("Vienna")).toBeTruthy();
});

test("city database has San Juan", () => {
  expect(isCity("San Juan")).toBeTruthy();
});

describe("when loading cities from the api", () => {
  let consoleWarnSpy = jest.spyOn(console, "warn");
  loadCities.mockResolvedValue(["Wellington", "London"]);

  it("does not duplicate cities", async () => {
    await database.loadCities();
    expect(database.cities).toHaveLength(4);
  });
});
clearCityDatabase();
```

以下是此规则的**正确**代码示例：

```javascript
import { database, isCity } from "../database";
import { Logger } from "../../../src/Logger";
import { loadCities } from "../api";

jest.mock("../api");
const initializeCityDatabase = () => {
  database.addCity("Vienna");
  database.addCity("San Juan");
  database.addCity("Wellington");
};

const clearCityDatabase = () => {
  database.clear();
};

beforeEach(() => {
  initializeCityDatabase();
});

test("that persists cities", () => {
  expect(database.cities.length).toHaveLength(3);
});

test("city database has Vienna", () => {
  expect(isCity("Vienna")).toBeTruthy();
});

test("city database has San Juan", () => {
  expect(isCity("San Juan")).toBeTruthy();
});

describe("when loading cities from the api", () => {
  let consoleWarnSpy;
  beforeEach(() => {
    consoleWarnSpy = jest.spyOn(console, "warn");
    loadCities.mockResolvedValue(["Wellington", "London"]);
  });

  it("does not duplicate cities", async () => {
    await database.loadCities();
    expect(database.cities).toHaveLength(4);
  });
});
afterEach(() => {
  clearCityDatabase();
});
```

## 配置

此规则接受一个包含以下属性的配置对象：

### allowedFunctionCalls

type: `string[]`

default: `[]`

允许在 hooks 之外调用的函数名数组。

## 使用方法

## 版本

此规则于 v0.3.2 中添加。

## 参考资料