> ## Documentation Index
> Fetch the complete documentation index at: https://bun.zhcndoc.com/llms.txt
> Use this file to discover all available pages before exploring further.

# 在 `bun test` 中使用模拟函数

使用 `bun:test` 中的 `mock` 函数创建模拟。

```ts test.ts icon="https://mintcdn.com/bun-zhcndoc/cnUTwgMuf4cCrwC-/icons/typescript.svg?fit=max&auto=format&n=cnUTwgMuf4cCrwC-&q=85&s=e7767043c9e885c34f2d6c8fe2a95217" theme={"theme":{"light":"github-light","dark":"dracula"}}
import { test, expect, mock } from "bun:test";

const random = mock(() => Math.random());
```

***

`mock` 函数可以接受参数。

```ts test.ts icon="https://mintcdn.com/bun-zhcndoc/cnUTwgMuf4cCrwC-/icons/typescript.svg?fit=max&auto=format&n=cnUTwgMuf4cCrwC-&q=85&s=e7767043c9e885c34f2d6c8fe2a95217" theme={"theme":{"light":"github-light","dark":"dracula"}}
import { test, expect, mock } from "bun:test";

const random = mock((multiplier: number) => multiplier * Math.random());
```

***

`mock()` 的结果是一个新的函数，并附加了一些额外的属性。

```ts test.ts icon="https://mintcdn.com/bun-zhcndoc/cnUTwgMuf4cCrwC-/icons/typescript.svg?fit=max&auto=format&n=cnUTwgMuf4cCrwC-&q=85&s=e7767043c9e885c34f2d6c8fe2a95217" theme={"theme":{"light":"github-light","dark":"dracula"}}
import { mock } from "bun:test";

const random = mock((multiplier: number) => multiplier * Math.random());

random(2);
random(10);

random.mock.calls;
// [[ 2 ], [ 10 ]]

random.mock.results;
//  [
//    { type: "return", value: 0.6533907460954099 },
//    { type: "return", value: 0.6452713933037312 }
//  ]
```

***

这些额外的属性使得可以编写关于模拟函数使用情况的 `expect` 断言，包括调用次数、参数和返回值。

```ts test.ts icon="https://mintcdn.com/bun-zhcndoc/cnUTwgMuf4cCrwC-/icons/typescript.svg?fit=max&auto=format&n=cnUTwgMuf4cCrwC-&q=85&s=e7767043c9e885c34f2d6c8fe2a95217" theme={"theme":{"light":"github-light","dark":"dracula"}}
import { test, expect, mock } from "bun:test";

const random = mock((multiplier: number) => multiplier * Math.random());

test("random", async () => {
  const a = random(1);
  const b = random(2);
  const c = random(3);

  expect(random).toHaveBeenCalled();
  expect(random).toHaveBeenCalledTimes(3);
  expect(random.mock.calls).toEqual([[1], [2], [3]]);
  expect(random.mock.results[0]).toEqual({ type: "return", value: a });
});
```

***

更多关于 Bun 测试运行器中模拟的完整文档，请参见[文档 > 测试运行器 > 模拟](/test/mocks)。