一、要记住的一些东西
1. 首先要明确用户的需求,然后列出需求,首先写测试代码。(也就是先从用户这方调用功能)
2. 看到红灯,则明白需要写程序代码。即写功能代码。
3. 一直到绿灯,然后看是否需要重构。
4. 在重构过后,继续写测试代码,增加用户功能调用,然后重复上述过程,就是测试驱动开发的力量。
5. 测试代码比文档更具有说服力,不仅让用户让测试程序员更加明白你的类是如何使用的。
6. Kent Beck把TDD定义为以下两个简单的规则:1)除非你在自动测试中失败,否则一行代码也不要写;2)消除重复(包括测试代码在内)。
二、第一个基于TDD的程序
(1)需求:一个保存文章的类Article,用于我以后将会开发的Web项目中。此Article类包括功能如下:
1. 创建一个Article,IsDirty为false;
2. 修改Article的Title后,IsDirty为true;
3. 修改Article的Title后,要查看是否真的修改了Title的值;
4. 调用Article的Save后,IsDirty为false,可代表已将文章保存到数据库中。
其它的功能,以后的文章中会渐进地实现。
(2)编写测试代码(使用了VS2005中的测试项目)
![](https://www.cnblogs.com/Images/OutliningIndicators/ContractedBlock.gif)
ArticleTest
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using System;
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using System.Text;
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using System.Collections.Generic;
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using Microsoft.VisualStudio.TestTools.UnitTesting;
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namespace FirstTDDProject
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![](https://www.cnblogs.com/Images/OutliningIndicators/ContractedBlock.gif)
{
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/**//// <summary>
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/// ArticleTest 的摘要说明
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/// </summary>
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[TestClass]
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public class ArticleTest
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{
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public ArticleTest()
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{
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}
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其他测试属性#region 其他测试属性
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//
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// 您可以在编写测试时使用下列其他属性:
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//
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// 在运行类中的第一个测试之前使用 ClassInitialize 运行代码
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// [ClassInitialize()]
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// public static void MyClassInitialize(TestContext testContext) { }
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//
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// 在类中的所有测试都已运行之后使用 ClassCleanup 运行代码
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// [ClassCleanup()]
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// public static void MyClassCleanup() { }
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//
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// 在运行每个测试之前使用 TestInitialize 运行代码
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// [TestInitialize()]
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// public void MyTestInitialize() { }
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//
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// 在运行每个测试之后使用 TestCleanup 运行代码
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// [TestCleanup()]
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// public void MyTestCleanup() { }
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//
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#endregion
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protected Article _art;
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[TestInitialize()]
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public void Initialize()
{
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_art = new Article();
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}
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[TestMethod]
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public void CheckIsDirty()
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{
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Assert.IsFalse(_art.IsDirty);
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}
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[TestMethod]
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public void ChangeTitle()
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{
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_art.Title = "NewTitle";
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Assert.IsTrue(_art.IsDirty, "After changing the Article.Title ,Article.IsDirty should be true.");
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}
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[TestMethod]
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public void ChangeTitleVerify()
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{
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_art.Title = "The first TDD Application.";
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Assert.AreEqual(_art.Title, "The first TDD Application.",
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"After changing the Article.Title ,Article.Title should be 'The first TDD Application..' .");
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}
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[TestMethod]
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public void SaveArticle()
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{
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_art.Title = "The first TDD Application.";
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_art.Save();
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Assert.IsFalse(_art.IsDirty, "After Saving the Article ,Article.IsDirty should be false.");
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}
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}
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}
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使用NUint编写的单元测试
![](https://www.cnblogs.com/Images/OutliningIndicators/ContractedBlock.gif)
ArticleTestWithNUnit
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using System;
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using System.Collections.Generic;
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using System.Text;
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using NUnit.Framework;
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namespace FirstTDDProject
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![](https://www.cnblogs.com/Images/OutliningIndicators/ContractedBlock.gif)
{
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[TestFixture]
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public class ArticleTestWithNUnit
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{
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protected Article _art;
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[SetUp]
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public void Init()
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{
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_art = new Article();
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}
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[Test]
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public void CheckIsDirty()
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{
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Assert.IsFalse(_art.IsDirty);
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}
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[Test]
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public void ChangeTitle()
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{
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_art.Title = "NewTitle";
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Assert.IsFalse(_art.IsDirty, "After changing the Article.Title ,Article.IsDirty should be true.");
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}
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[Test]
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public void ChangeTitleVerify()
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{
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_art.Title = "The first TDD Application.";
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Assert.AreEqual(_art.Title, "The first TDD Application.",
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"After changing the Article.Title ,Article.Title should be 'The first TDD Application..' .");
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}
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[Test]
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public void SaveArticle()
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{
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_art.Title = "The first TDD Application.";
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_art.Save();
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Assert.IsTrue(_art.IsDirty, "After Saving the Article ,Article.IsDirty should be false.");
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}
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}
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}
49![](https://www.cnblogs.com/Images/OutliningIndicators/None.gif)
根据测试代码一步步完善的Article代码
![](https://www.cnblogs.com/Images/OutliningIndicators/ContractedBlock.gif)
Article
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using System;
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using System.Collections.Generic;
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using System.Text;
4![](https://www.cnblogs.com/Images/OutliningIndicators/None.gif)
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namespace FirstTDDProject
6![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedBlockStart.gif)
![](https://www.cnblogs.com/Images/OutliningIndicators/ContractedBlock.gif)
{
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public class Article
8![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
{
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private bool _isDirty;
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private string _title;
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private string _body;
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public string Body
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{
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get
{ return _body; }
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set
{
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_body = value;
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_isDirty = true;
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}
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}
21![](https://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif)
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public string Title
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{
24![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
get
{ return _title; }
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set
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{
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_title = value;
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_isDirty = true;
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}
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}
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public bool IsDirty
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{
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get
{ return _isDirty; }
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}
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37![](https://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif)
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public Article()
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{
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_isDirty = false;
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}
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public void Save()
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{
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_isDirty = false;
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}
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}
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}
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本文参考了Visual Studio 2005 Team System的测试驱动开发。