Migrate tests from Jest + jest-electron to Playwright (Chromium only)

[Copilot]

Migration Plan: Jest + jest-electron → Playwright (Chromium only)

Related Issue: #23

Checklist:

• 1. Install Playwright dependencies
  • Add @playwright/test as devDependency
  • Remove jest, jest-electron, and babel-jest from package.json
• 2. Update package.json scripts
  • Change test script to use Playwright
  • Remove debug script (Jest-specific)
  • Remove jest configuration block
• 3. Create Playwright configuration
  • Add playwright.config.mjs with Chromium-only project
  • Configure testDir to use tests/ directory
  • Set up headless mode for CI
  • Use .mjs extension for ES module support
• 4. Migrate test files from tests/ to tests/
  • Migrate index.spec.mjs - test exports (bind, clear, ver) and demo functionality
  • Migrate unbind.spec.mjs - test clear() and unbind() functions
  • Migrate issue-17.spec.mjs - test memory leak fix from issue 只调用 unbind 不调用 clear 的话存在内存泄漏 #17
  • Use .mjs extension for ES module support
• 5. Update GitHub Actions workflow
  • Add Playwright browser installation step before tests
  • Keep existing workflow structure intact
• 6. Verify everything works
  • Build process verified
  • Old tests directory removed
  • Fixed CI error (ES module support)
  • Added package-lock.json to .gitignore

Decision: Running Chromium only to keep the setup lightweight and fast, while still providing browser-based DOM testing that was previously done with jest-electron.

Technical Approach:

• Tests load the pre-built UMD bundle (dist/size-sensor.min.js) into Playwright pages
• DOM manipulation and assertions run in browser context via page.evaluate()
• Tests maintain the same coverage as original Jest tests
• Using .mjs extension for proper ES module support in Node.js

Original prompt

在仓库 hustcc/size-sensor 基于 master 创建一个 PR，将测试从 jest + jest-electron 迁移到 Playwright（只跑 Chromium），并尽量保持修改精准。

上下文：

• Issue: https://github.com/hustcc/size-sensor/issues/23
• 现有 jest 配置在 package.json，并使用 jest-electron runner/environment。
• 现有测试文件在 __tests__/：index.spec.js、unbind.spec.js、issue-17.spec.js。
• 现有 GitHub Actions workflow（参考 ref b9be27ef358a32546110c011bc2fa587e23ec62e）在 .github/workflows/build.yml，会执行 npm test。
  • 链接（需使用该 ref）：https://github.com/hustcc/size-sensor/blob/b9be27ef358a32546110c011bc2fa587e23ec62e/.github/workflows/build.yml

需求与改动范围：

1. 替换测试框架：移除 jest、jest-electron、babel-jest，新增 @playwright/test。
2. 更新 package.json scripts：将 npm test 改为运行 Playwright（例如 playwright test），并确保 CI 继续使用 npm test 即可。
3. 新增 Playwright 配置：
   • 配置只运行 Chromium（单 project），CI 模式下可使用 headless。
   • 选择合理的 testDir（例如 tests/），并匹配现有用例。
4. 迁移测试用例：将 __tests__/ 下三个用例迁移到 Playwright：
   • 保留原测试意图与断言（export/ver、bind/clear/unbind、只调用 unbind 不调用 clear 的话存在内存泄漏 #17 memory leak）。
   • 在浏览器环境中执行 DOM 操作与 getComputedStyle（通过 page.setContent + page.evaluate 等方式）。
   • 尽量不改动库源码；如必须加载库代码到浏览器，可采用最小方案（例如直接在测试里注入 src 代码的 bundle，或在测试前构建 dist 并注入）。
5. 更新 GitHub Actions（如必要）：
   • 增加 Playwright 浏览器安装步骤（例如 npx playwright install --with-deps chromium），确保在 macOS runner 上能跑。
   • 尽量保持 workflow 其余部分不变。
6. PR 说明：在 PR 描述中关联 issue #23，并说明只跑 Chromium 的决定。

验收标准：

• npm test 在本地/CI 可运行并通过。
• 不再依赖 jest/jest-electron。
• Playwright 测试覆盖原 3 个 spec 的核心断言。
• Playwright 配置只跑 Chromium。

This pull request was created from Copilot chat.

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[hustcc]

@copilot ci 执行报错了处理一下。

另外把 lock 文件 git ignore

[Copilot]

@copilot ci 执行报错了处理一下。

另外把 lock 文件 git ignore

Fixed in commit a9d5bb1:

1. CI Error: Renamed config and test files from .js to .mjs to properly support ES modules in Node.js
2. package-lock.json: Added to .gitignore and removed from git tracking

The ES module error was caused by using import syntax in .js files without Node.js knowing they're ES modules. Using .mjs extension tells Node.js to treat them as ES modules directly.