Playwright NUnit测试问题：Page对象未初始化或测试无法运行

问题1：测试资源管理器无匹配测试 #

按官方文档实现但找不到测试，大概率是以下两个原因：

• 项目未正确引用NUnit测试框架及适配包：确保已安装NUnit、NUnit3TestAdapter和Microsoft.NET.Test.Sdk NuGet包，这些是NUnit测试被识别的必要条件。
• 误用了MSTest特性而非NUnit特性：Playwright官方NUnit示例用的是NUnit原生特性，测试类需标记[TestFixture]，测试方法标记[Test]，而非MSTest的[TestClass]/[TestMethod]。正确结构示例：

using NUnit.Framework;
using Microsoft.Playwright;

namespace YourNamespace
{
    [TestFixture]
    public class ExampleTests
    {
        private IPage _page;
        private IPlaywright _playwright;
        private IBrowser _browser;

        [SetUp]
        public async Task SetUp()
        {
            _playwright = await Playwright.CreateAsync();
            _browser = await _playwright.Chromium.LaunchAsync();
            _page = await _browser.NewPageAsync();
        }

        [Test]
        public async Task TestGoogleSearch()
        {
            await _page.GotoAsync("https://www.google.com");
            // 测试逻辑
        }

        [TearDown]
        public async Task TearDown()
        {
            await _browser.CloseAsync();
            _playwright.Dispose();
        }
    }
}

问题2：添加MSTest特性后出现NullReferenceException #

你添加的[TestClass]和[TestMethod]是MSTest框架的特性，而Playwright对NUnit的支持基于NUnit的生命周期和依赖注入机制，MSTest不兼容Playwright默认的Page注入方式，直接替换特性会导致_page等对象未初始化，进而抛出空引用异常。

解决方式：

• 切换回NUnit特性：移除[TestClass]和[TestMethod]，改用NUnit的[TestFixture]和[Test]，同时确保项目依赖NUnit相关包而非MSTest。
• 若坚持用MSTest：需手动初始化Playwright、Browser和Page对象，不能依赖自动注入。示例结构：

using Microsoft.VisualStudio.TestTools.UnitTesting;
using Microsoft.Playwright;

namespace YourNamespace
{
    [TestClass]
    public class ExampleMsTests
    {
        private IPage _page;
        private IPlaywright _playwright;
        private IBrowser _browser;

        [TestInitialize]
        public async Task TestInitialize()
        {
            _playwright = await Playwright.CreateAsync();
            _browser = await _playwright.Chromium.LaunchAsync(new BrowserTypeLaunchOptions { Headless = false });
            _page = await _browser.NewPageAsync();
        }

        [TestMethod]
        public async Task TestGoogleSearch()
        {
            await _page.GotoAsync("https://www.google.com");
            // 测试逻辑
        }

        [TestCleanup]
        public async Task TestCleanup()
        {
            await _browser.CloseAsync();
            _playwright.Dispose();
        }
    }
}

额外注意事项：

• 确保安装对应集成包：用NUnit则装Microsoft.Playwright.NUnit，用MSTest则装Microsoft.Playwright.MSTest。
• 首次运行前执行playwright install命令，安装浏览器驱动，避免启动浏览器失败。

内容的提问来源于stack exchange，提问作者Mandelbrotter