bun-test

Bun 测试配置

配置 Bun 内置测试运行器，使用兼容 Jest 的 API，并显著提升执行速度（比 Jest 快 3–10 倍）。

快速参考

如需了解详细模式，请参阅：

• Jest 迁移：jest-migration.md - 完整的 Jest 到 Bun 迁移指南
• 模拟：mocking.md - 模拟函数、间谍和模块
• 示例：examples.md - API、数据库和异步代码的测试模式

核心工作流

1. 检查先决条件

# Verify Bun installation
bun --version

# Check if project exists
ls -la package.json

2. 确定测试需求

询问用户需要哪种类型的测试：

• 单元测试：测试单个函数和模块
• 集成测试：测试组件交互
• API 测试：测试 HTTP 端点
• 快照测试：测试输出一致性

3. 创建测试目录结构

# Create test directories
mkdir -p tests/{unit,integration,fixtures}

推荐结构：

project/
├── src/
│   ├── utils.ts
│   └── components/
├── tests/
│   ├── unit/              # Unit tests
│   ├── integration/       # Integration tests
│   ├── fixtures/          # Test data
│   └── setup.ts          # Global setup
├── package.json
└── bunfig.toml           # Test configuration

4. 配置 Bun 测试

在项目根目录中创建 bunfig.toml：

[test]
# Preload files before running tests
preload = ["./tests/setup.ts"]

# Code coverage
coverage = true
coverageDir = "coverage"
coverageThreshold = 80

# Timeouts (in milliseconds)
timeout = 5000

# Bail after first failure
bail = false

5. 创建测试设置文件

创建 tests/setup.ts：

import { beforeAll, afterAll, beforeEach, afterEach } from "bun:test";

// Global test setup
beforeAll(() => {
  console.log("🧪 Starting test suite");
  process.env.NODE_ENV = "test";
});

afterAll(() => {
  console.log("✅ Test suite complete");
});

// Reset mocks before each test
beforeEach(() => {
  // Clear mock state
});

afterEach(() => {
  // Cleanup after each test
});

// Global test utilities
globalThis.testHelpers = {
  wait: (ms: number) => new Promise(resolve => setTimeout(resolve, ms)),
};

6. 编写第一个测试

创建 tests/unit/example.test.ts：

import { describe, it, expect, test } from "bun:test";

// Simple test
test("addition works", () => {
  expect(1 + 1).toBe(2);
});

// Describe blocks for organization
describe("Array utilities", () => {
  it("should filter even numbers", () => {
    const numbers = [1, 2, 3, 4, 5, 6];
    const evens = numbers.filter(n => n % 2 === 0);

    expect(evens).toEqual([2, 4, 6]);
    expect(evens).toHaveLength(3);
  });
});

// Async tests
describe("Async operations", () => {
  it("should handle promises", async () => {
    const result = await Promise.resolve(42);
    expect(result).toBe(42);
  });
});

如需查看更多测试示例（API 测试、数据库测试等），请参阅 examples.md。

7. 添加模拟（如有需要）

import { describe, it, expect, mock, spyOn } from "bun:test";

describe("Mock functions", () => {
  it("should create mock functions", () => {
    const mockFn = mock((x: number) => x * 2);

    const result = mockFn(5);

    expect(result).toBe(10);
    expect(mockFn).toHaveBeenCalledTimes(1);
    expect(mockFn).toHaveBeenCalledWith(5);
  });

  it("should spy on methods", () => {
    const obj = {
      method: (x: number) => x * 2,
    };

    const spy = spyOn(obj, "method");

    obj.method(5);

    expect(spy).toHaveBeenCalledWith(5);
    expect(spy).toHaveReturnedWith(10);
  });
});

如需了解高级模拟模式，请参阅 mocking.md。

8. 更新 package.json

添加测试脚本：

{
  "scripts": {
    "test": "bun test",
    "test:watch": "bun test --watch",
    "test:coverage": "bun test --coverage",
    "test:ui": "bun test --coverage --reporter=html"
  }
}

9. 运行测试

# Run all tests
bun test

# Run specific file
bun test tests/unit/utils.test.ts

# Watch mode
bun test --watch

# With coverage
bun test --coverage

# Filter by name
bun test --test-name-pattern="should handle"

Jest 迁移

如果要从 Jest 迁移，请参阅 jest-migration.md，了解：

• 导入更新（@jest/globals → bun:test）
• 模拟语法变更（jest.fn() → mock()）
• 配置迁移
• 兼容性说明

主要变更：

// Before (Jest)
import { describe, it, expect } from '@jest/globals';
const mockFn = jest.fn();

// After (Bun)
import { describe, it, expect, mock } from 'bun:test';
const mockFn = mock();

常见测试模式

测试函数

import { test, expect } from "bun:test";

function add(a: number, b: number): number {
  return a + b;
}

test("add function", () => {
  expect(add(2, 3)).toBe(5);
  expect(add(-1, 1)).toBe(0);
});

测试错误

test("should throw errors", () => {
  const throwError = () => {
    throw new Error("Something went wrong");
  };

  expect(throwError).toThrow("Something went wrong");
  expect(throwError).toThrow(Error);
});

test("should reject promises", async () => {
  const asyncReject = async () => {
    throw new Error("Async error");
  };

  await expect(asyncReject()).rejects.toThrow("Async error");
});

快照测试

test("should match snapshot", () => {
  const data = {
    id: 1,
    name: "Test User",
    email: "[email protected]",
  };

  expect(data).toMatchSnapshot();
});

test("should match inline snapshot", () => {
  const config = { theme: "dark", language: "en" };

  expect(config).toMatchInlineSnapshot(`
    {
      "theme": "dark",
      "language": "en"
    }
  `);
});

匹配器参考

常见的可用匹配器：

// Equality
expect(value).toBe(expected);           // ===
expect(value).toEqual(expected);        // Deep equality

// Truthiness
expect(value).toBeTruthy();
expect(value).toBeFalsy();
expect(value).toBeDefined();
expect(value).toBeUndefined();

// Numbers
expect(number).toBeGreaterThan(3);
expect(number).toBeLessThan(5);

// Strings
expect(string).toMatch(/pattern/);
expect(string).toContain("substring");

// Arrays
expect(array).toContain(item);
expect(array).toHaveLength(3);

// Objects
expect(object).toHaveProperty("key");
expect(object).toMatchObject({ subset });

// Promises
await expect(promise).resolves.toBe(value);
await expect(promise).rejects.toThrow();

// Mock functions
expect(mockFn).toHaveBeenCalled();
expect(mockFn).toHaveBeenCalledTimes(3);
expect(mockFn).toHaveBeenCalledWith(arg1, arg2);

测试组织

设置和清理

import { beforeAll, afterAll, beforeEach, afterEach, describe, it } from "bun:test";

describe("User service", () => {
  let db: Database;

  beforeAll(async () => {
    // Setup before all tests
    db = await connectToDatabase();
  });

  afterAll(async () => {
    // Cleanup after all tests
    await db.close();
  });

  beforeEach(async () => {
    // Reset before each test
    await db.clear();
  });

  it("should create user", async () => {
    const user = await db.users.create({ name: "Test" });
    expect(user.id).toBeDefined();
  });
});

覆盖率配置

查看覆盖率报告：

# Generate coverage
bun test --coverage

# View HTML report
bun test --coverage --reporter=html
open coverage/index.html

在 bunfig.toml 中设置覆盖率阈值：

[test]
coverage = true
coverageThreshold = 80  # Fail if coverage < 80%

调试测试

# Run with debugger
bun test --inspect

# Verbose output
bun test --verbose

# Show all test results
bun test --reporter=tap

性能

Bun 测试的速度显著快于 Jest：

• Jest：100 个测试约需 15 秒
• Bun：100 个测试约需 2 秒

执行速度快 3–10 倍！

完成检查清单

• ✅ 已创建测试目录结构
• ✅ 已配置 bunfig.toml
• ✅ 已创建测试设置文件
• ✅ 已编写示例测试
• ✅ 已更新 package.json 脚本
• ✅ 测试运行成功
• ✅ 已配置覆盖率（如有需要）

后续步骤

完成基本设置后：

1. 编写测试：为关键业务逻辑添加测试
2. CI/CD：配置测试在流水线中运行
3. 覆盖率：设置覆盖率报告
4. 提交前检查：添加提交前钩子以运行测试
5. 文档：为团队记录测试模式

如需了解详细实现，请参阅上方链接的参考文件。