走进 .Net 单元测试

走进 .Net 单元测试

Intro

“不会写单元测试的程序员不是合格的程序员，不写单元测试的程序员不是优秀程序员。”

—— 一只想要成为一个优秀程序员的渣逼程序猿。

那么问题来了，什么是单元测试，如何做单元测试。

单元测试定义

按照维基百科上的说法，单元测试（Unit Testing）又称为模块测试, 是针对程序模块（软件设计的最小单位）来进行正确性检验的测试工作。 程序单元是应用的最小可测试部件。在面向对象编程中，最小单元就是方法，包括基类、抽象类、或者派生类（子类）中的方法。 按照通俗的理解，一个单元测试判断某个特定场条件下某个特定方法的行为，如斐波那契数列算法，冒泡排序算法。

单元测试（unit testing），是指对软件中的最小可测试单元进行检查和验证。 对于单元测试中单元的含义，一般来说，要根据实际情况去判定其具体含义， 如C语言中单元指一个函数，Java里单元指一个类，图形化的软件中可以指一个窗口或一个菜单等。 总的来说，单元就是人为规定的最小的被测功能模块。 单元测试是在软件开发过程中要进行的最低级别的测试活动，软件的独立单元将在与程序的其他部分相隔离的情况下进行测试。

—— 百度百科 http://baike.baidu.com/view/106237.htm

进行单元测试的好处

1. 它是一种验证行为

   程序中的每一项功能都是测试来验证它的正确性。

2. 它是一种设计行为

   编写单元测试将使我们从调用者观察、思考。 特别是先写测试（test-first），迫使我们把程序设计成易于调用和可测试的，有利于程序的解耦和模块化。

3. 它是一种编写文档的行为

   单元测试是一种无价的文档，它是展示函数或类如何使用的最佳文档。这份文档是可编译、可运行的，并且它保持最新，永远与代码同步。

4. 它具有回归性

   自动化的单元测试避免了代码出现回归，编写完成之后，可以随时随地的快速运行测试。

5. 高效

   自动化的单元测试节省了开发上调试BUG的时间，绝大多数BUG可以通过单元测试测试出来，并且可以减少测试人员的测试时间。有时候通过写单元测试能够更好的完善自己程序的逻辑，让程序变得更加美好。

   —— 单元测试的优点 http://jingyan.baidu.com/article/d713063522ab4e13fdf47533.html

单元测试的原则：

• 可重复运行的
• 持续长期有效，并且返回一致的结果
• 在内存中运行，没有外部依赖组件（比如说真实的数据库，真实的文件存储等）
• 快速返回结果
• 一个测试方法只测试一个问题

VS单元测试 【MsTest】使用

VS单元测试的主要类：Assert、StringAssert、CollectionAssert，具体可参照 MSDN介绍

有些时候我们需要对测试的方法用到的数据或配置进行初始化，有几个特殊的测试方法。

如果需要针对测试中的所有虚拟用户迭代仅执行一次初始化操作，请使用 TestInitializeAttribute。

初始化方法的运行顺序如下：

1. 用 AssemblyInitializeAttribute 标记的方法。
2. 用 ClassInitializeAttribute 特性标记的方法。
3. 用 TestInitializeAttribute 特性标记的方法。
4. 用 TestMethodAttribute 特性标记的方法。

单元测试 使用示例 

using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace ConsoleApplication1Test
{
    [TestClass]
    public class MainTest
    {
        #region TestFail

        [TestMethod]
        public void TestFail0()
        {
            Assert.Fail();
        }

        [TestMethod]
        public void TestFail1()
        {
            Assert.Fail("Test is fail");
        }

        [TestMethod]
        public void TestFail2()
        {
            Assert.Fail("Test3 is fail,{0}", "hahaha");
        }
        #endregion

        #region TestInconclusive 忽略
        [TestMethod]
        public void TestInconclusive0()
        {
            Assert.Inconclusive();
        }

        [TestMethod]
        public void TestInconclusive1()
        {
            Assert.Inconclusive("Inconclusive");
        }

        [TestMethod]
        public void TestInconclusive2()
        {
            Assert.Inconclusive("Inconclusive,{0}", "hehehe");
        }
        #endregion

        #region LogicTest

        #region Null
        [TestMethod]
        public void IsNullTest()
        {
            Assert.IsNull(null);
        }

        [TestMethod]
        public void IsNotNullTest()
        {
            Assert.IsNotNull(1);
        } 
        #endregion

        #region True || False
        [TestMethod]
        public void IsTrueTest()
        {
            Assert.IsTrue(1 == 1);
        }

        [TestMethod]
        public void IsFalseTest()
        {
            Assert.IsFalse(1 > 2);
        } 
        #endregion

        #region AreSame
        [TestMethod]
        public void AreSameTest()
        {
            //不要向 AreSame() 传递值类型的值，因为他们转换为 Object 后永久不会相等，值类型的值比较请使用 AreEqual()
            Assert.AreSame(1, 1);
        }

        [TestMethod]
        public void AreSameTest1()
        {
            object obj = new object(), obj1 = obj;
            Assert.AreSame(obj, obj1, "same");
        }

        [TestMethod]
        public void StringAreSameTest0()
        {
            string str1 = "hello", str2 = "hello";
            Assert.AreSame(str1, str2);
        }

        [TestMethod]
        public void StringAreSameTest1()
        {
            string str1 = "hello", str2 = "Hello";
            Assert.AreSame(str1, str2);
        }

        [TestMethod]
        public void AreNotSameTest()
        {
            object obj = new object(), obj1 = new object();
            Assert.AreNotSame(obj, obj1);
        } 
        #endregion

        #region AreEqual
        [TestMethod]
        public void AreEqualTest()
        {
            Assert.AreEqual(1, 1);
        }

        [TestMethod]
        public void AreNotEqualTest()
        {
            Assert.AreNotEqual(1, 2);
        }

        [TestMethod]
        public void AreEqualTest1()
        {
            object obj = new object(), obj1 = obj;
            Assert.AreEqual(obj, obj1);
        }

        [TestMethod]
        public void AreNotEqualTest1()
        {
            object obj = new object(), obj1 = new object();
            Assert.AreNotEqual(obj, obj1);
        }

        [TestMethod]
        public void AreEqualTest2()
        {
            object obj = new object(), obj1 = new object();
            Assert.AreEqual(obj, obj1);
            // Assert.Equals()不用于断言，请使用 Assert.AreEquals() 或 Assert.AreNotEquals()
            //Assert.Equals(obj, obj1);
        }

        [TestMethod]
        public void StringAreEqualTest0()
        {
            string str = "hello", str1 = "hello";
            Assert.AreEqual(str, str1);
        }

        [TestMethod]
        public void StringAreEqualTest1()
        {
            string str = "hello", str1 = "Hello";
            Assert.AreEqual(str, str1, true);
        } 
        #endregion

        #region IsInstanceOfType

        [TestMethod]
        public void IsInstanceOfTypeTest()
        {
            B b = new B();
            Assert.IsInstanceOfType(b, typeof(A));
        }

        [TestMethod]
        public void IsNotInstanceOfTypeTest()
        {
            A a = new A();
            Assert.IsNotInstanceOfType(a, typeof(B));
        }
        #endregion

        #endregion

        #region 测试初始化和清理
        [AssemblyInitialize()]
        public static void AssemblyInit(TestContext context)
        {
            System.Console.WriteLine("AssemblyInit " + context.TestName);
        }

        [ClassInitialize()]
        public static void ClassInit(TestContext context)
        {
            System.Console.WriteLine("ClassInit " + context.TestName);
        }

        [TestInitialize]
        public void Initialize()
        {
            System.Console.WriteLine("TestMethodInit");
        }

        [TestCleanup]
        public void Cleanup()
        {
            System.Console.WriteLine("TestMethodCleanup");
        }

        [ClassCleanup]
        public static void ClassCleanup()
        {
            System.Console.WriteLine("ClassCleanup");
        }

        [AssemblyCleanup]
        public static void AssemblyCleanup()
        {
            System.Console.WriteLine("AssemblyCleanup");
        } 
        #endregion
    }

    public class A { }

    public class B : A { }

}

MsTest 和 Nunit区别

MS Test框架是Visual Studio自带的测试框架，可以通过新建一个Unit Test Project工程， 也可以建一个Class Libary，然后添加对Microsoft.VisualStudio.QualityTools.UnitTestFramework.dll的引用。 然后就是创建测试用例，进行测试即可。

NUnit Test框架是一个xUnit家族种的第4个主打产品，完全由C#语言来编写，支持所有的.Net语言。 使用NUnit框架，我们需要下载安装包，安装后使用独立客户端进行使用。使用方法与MS Test类似

有一些是NUnit中的，但是MS Test框架中是没有的： - Assert.IsNaN - Assert.IsEmpty - Assert.IsNotEmpty - Assert.Greater - Assert.GreaterOrEqual - Assert.Less - Assert.LessOrEqual - Assert.IsAssignableFrom - Assert.IsNotAssignableFrom - Assert.Igore - CollectionAssert.IsEmpty - CollectionAssert.IsNotEmpty - StringAssert.AreEqualIgnoringCase - StringAssert.IsMatch - FileAssert.AreEqual - FileAssert.AreNotEqual

同时支持两种测试框架

可以通过宏判断来同时支持这两个框架，在测试前添加以下代码： 

#if !NUNIT 
using Microsoft.VisualStudio.TestTools.UnitTesting; 
using Category = Microsoft.VisualStudio.TestTools.UnitTesting.DescriptionAttribute; 
#else 
using NUnit.Framework; 
using TestClass = NUnit.Framework.TestFixtureAttribute; 
using TestMethod = NUnit.Framework.TestAttribute; 
using TestInitialize = NUnit.Framework.SetUpAttribute; 
using TestCleanup = NUnit.Framework.TearDownAttribute; 
using TestContext = System.Object; 
using ClassCleanup = NUnit.Framework.TestFixtureTearDownAttribute; 
using ClassInitialize = NUnit.Framework.TestFixtureSetUpAttribute; 
#endif

Nunit测试使用示例

#region NUNIT

    /// <summary>
    /// This test fixture attempts to exercise all the syntactic
    /// variations of Assert without getting into failures, errors 
    /// or corner cases.Thus, some of the tests may be duplicated 
    /// in other fixtures.
    /// 
    /// Each test performs the same operations using the classic
    /// syntax(if available) and the new syntax in both the
    /// helper-based and inherited forms.
    /// 
    /// This Fixture will eventually be duplicated in other
    /// supported languages. 
    /// </summary>
    [TestFixture]
    public class AssertSyntaxTests : AssertionHelper
    {
        #region Simple Constraint Tests
        [Test]
        public void IsNull()
        {
            object nada = null;

            // Classic syntax
            Assert.IsNull(nada);

            // Constraint Syntax
            Assert.That(nada, Is.Null);

            // Inherited syntax
            Expect(nada, Null);
        }

        [Test]
        public void IsNotNull()
        {
            // Classic syntax
            Assert.IsNotNull(42);

            // Constraint Syntax
            Assert.That(42, Is.Not.Null);

            // Inherited syntax
            Expect(42, Not.Null);
        }

        [Test]
        public void IsTrue()
        {
            // Classic syntax
            Assert.IsTrue(2 + 2 == 4);

            // Constraint Syntax
            Assert.That(2 + 2 == 4, Is.True);
            Assert.That(2 + 2 == 4);

            // Inherited syntax
            Expect(2 + 2 == 4, True);
            Expect(2 + 2 == 4);
        }

        [Test]
        public void IsFalse()
        {
            // Classic syntax
            Assert.IsFalse(2 + 2 == 5);

            // Constraint Syntax
            Assert.That(2 + 2 == 5, Is.False);

            // Inherited syntax
            Expect(2 + 2 == 5, False);
        }

        [Test]
        public void IsNaN()
        {
            double d = double.NaN;
            float f = float.NaN;

            // Classic syntax
            Assert.IsNaN(d);
            Assert.IsNaN(f);

            // Constraint Syntax
            Assert.That(d, Is.NaN);
            Assert.That(f, Is.NaN);

            // Inherited syntax
            Expect(d, NaN);
            Expect(f, NaN);
        }

        [Test]
        public void EmptyStringTests()
        {
            // Classic syntax
            Assert.IsEmpty("");
            Assert.IsNotEmpty("Hello!");

            // Constraint Syntax
            Assert.That("", Is.Empty);
            Assert.That("Hello!", Is.Not.Empty);

            // Inherited syntax
            Expect("", Empty);
            Expect("Hello!", Not.Empty);
        }

        [Test]
        public void EmptyCollectionTests()
        {
            // Classic syntax
            Assert.IsEmpty(new bool[0]);
            Assert.IsNotEmpty(new int[] { 1, 2, 3 });

            // Constraint Syntax
            Assert.That(new bool[0], Is.Empty);
            Assert.That(new int[] { 1, 2, 3 }, Is.Not.Empty);

            // Inherited syntax
            Expect(new bool[0], Empty);
            Expect(new int[] { 1, 2, 3 }, Not.Empty);
        }
        #endregion

        #region TypeConstraint Tests
        [Test]
        public void ExactTypeTests()
        {
            // Classic syntax workarounds
            Assert.AreEqual(typeof(string), "Hello".GetType());
            Assert.AreEqual("System.String", "Hello".GetType().FullName);
            Assert.AreNotEqual(typeof(int), "Hello".GetType());
            Assert.AreNotEqual("System.Int32", "Hello".GetType().FullName);

            // Constraint Syntax
            Assert.That("Hello", Is.TypeOf(typeof(string)));
            Assert.That("Hello", Is.Not.TypeOf(typeof(int)));

            // Inherited syntax
            Expect("Hello", TypeOf(typeof(string)));
            Expect("Hello", Not.TypeOf(typeof(int)));
        }

        [Test]
        public void InstanceOfTests()
        {
            // Classic syntax
            Assert.IsInstanceOf(typeof(string), "Hello");
            Assert.IsNotInstanceOf(typeof(string), 5);

            // Constraint Syntax
            Assert.That("Hello", Is.InstanceOf(typeof(string)));
            Assert.That(5, Is.Not.InstanceOf(typeof(string)));

            // Inherited syntax
            Expect("Hello", InstanceOf(typeof(string)));
            Expect(5, Not.InstanceOf(typeof(string)));
        }

        [Test]
        public void AssignableFromTypeTests()
        {
            // Classic syntax
            Assert.IsAssignableFrom(typeof(string), "Hello");
            Assert.IsNotAssignableFrom(typeof(string), 5);

            // Constraint Syntax
            Assert.That("Hello", Is.AssignableFrom(typeof(string)));
            Assert.That(5, Is.Not.AssignableFrom(typeof(string)));

            // Inherited syntax
            Expect("Hello", AssignableFrom(typeof(string)));
            Expect(5, Not.AssignableFrom(typeof(string)));
        }
        #endregion

        #region StringConstraint Tests
        [Test]
        public void SubstringTests()
        {
            string phrase = "Hello World!";
            string[] array = new string[] { "abc", "bad", "dba" };

            // Classic Syntax
            StringAssert.Contains("World", phrase);

            // Constraint Syntax
            Assert.That(phrase, Does.Contain("World"));
            // Only available using new syntax
            Assert.That(phrase, Does.Not.Contain("goodbye"));
            Assert.That(phrase, Does.Contain("WORLD").IgnoreCase);
            Assert.That(phrase, Does.Not.Contain("BYE").IgnoreCase);
            Assert.That(array, Is.All.Contains("b"));

            // Inherited syntax
            Expect(phrase, Contains("World"));
            // Only available using new syntax
            Expect(phrase, Not.Contains("goodbye"));
            Expect(phrase, Contains("WORLD").IgnoreCase);
            Expect(phrase, Not.Contains("BYE").IgnoreCase);
            Expect(array, All.Contains("b"));
        }

        [Test]
        public void StartsWithTests()
        {
            string phrase = "Hello World!";
            string[] greetings = new string[] { "Hello!", "Hi!", "Hola!" };

            // Classic syntax
            StringAssert.StartsWith("Hello", phrase);

            // Constraint Syntax
            Assert.That(phrase, Does.StartWith("Hello"));
            // Only available using new syntax
            Assert.That(phrase, Does.Not.StartWith("Hi!"));
            Assert.That(phrase, Does.StartWith("HeLLo").IgnoreCase);
            Assert.That(phrase, Does.Not.StartWith("HI").IgnoreCase);
            Assert.That(greetings, Is.All.StartsWith("h").IgnoreCase);

            // Inherited syntax
            Expect(phrase, StartsWith("Hello"));
            // Only available using new syntax
            Expect(phrase, Not.StartsWith("Hi!"));
            Expect(phrase, StartsWith("HeLLo").IgnoreCase);
            Expect(phrase, Not.StartsWith("HI").IgnoreCase);
            Expect(greetings, All.StartsWith("h").IgnoreCase);
        }

        [Test]
        public void EndsWithTests()
        {
            string phrase = "Hello World!";
            string[] greetings = new string[] { "Hello!", "Hi!", "Hola!" };

            // Classic Syntax
            StringAssert.EndsWith("!", phrase);

            // Constraint Syntax
            Assert.That(phrase, Does.EndWith("!"));
            // Only available using new syntax
            Assert.That(phrase, Does.Not.EndWith("?"));
            Assert.That(phrase, Does.EndWith("WORLD!").IgnoreCase);
            Assert.That(greetings, Is.All.EndsWith("!"));

            // Inherited syntax
            Expect(phrase, EndsWith("!"));
            // Only available using new syntax
            Expect(phrase, Not.EndsWith("?"));
            Expect(phrase, EndsWith("WORLD!").IgnoreCase);
            Expect(greetings, All.EndsWith("!"));
        }

        [Test]
        public void EqualIgnoringCaseTests()
        {
            string phrase = "Hello World!";

            // Classic syntax
            StringAssert.AreEqualIgnoringCase("hello world!", phrase);

            // Constraint Syntax
            Assert.That(phrase, Is.EqualTo("hello world!").IgnoreCase);
            //Only available using new syntax
            Assert.That(phrase, Is.Not.EqualTo("goodbye world!").IgnoreCase);
            Assert.That(new string[] { "Hello", "World" },
                Is.EqualTo(new object[] { "HELLO", "WORLD" }).IgnoreCase);
            Assert.That(new string[] { "HELLO", "Hello", "hello" },
                Is.All.EqualTo("hello").IgnoreCase);

            // Inherited syntax
            Expect(phrase, EqualTo("hello world!").IgnoreCase);
            //Only available using new syntax
            Expect(phrase, Not.EqualTo("goodbye world!").IgnoreCase);
            Expect(new string[] { "Hello", "World" },
                EqualTo(new object[] { "HELLO", "WORLD" }).IgnoreCase);
            Expect(new string[] { "HELLO", "Hello", "hello" },
                All.EqualTo("hello").IgnoreCase);
        }

        [Test]
        public void RegularExpressionTests()
        {
            string phrase = "Now is the time for all good men to come to the aid of their country.";
            string[] quotes = new string[] { "Never say never", "It's never too late", "Nevermore!" };

            // Classic syntax
            StringAssert.IsMatch("all good men", phrase);
            StringAssert.IsMatch("Now.*come", phrase);

            // Constraint Syntax
            Assert.That(phrase, Does.Match("all good men"));
            Assert.That(phrase, Does.Match("Now.*come"));
            // Only available using new syntax
            Assert.That(phrase, Does.Not.Match("all.*men.*good"));
            Assert.That(phrase, Does.Match("ALL").IgnoreCase);
            Assert.That(quotes, Is.All.Matches("never").IgnoreCase);

            // Inherited syntax
            Expect(phrase, Matches("all good men"));
            Expect(phrase, Matches("Now.*come"));
            // Only available using new syntax
            Expect(phrase, Not.Matches("all.*men.*good"));
            Expect(phrase, Matches("ALL").IgnoreCase);
            Expect(quotes, All.Matches("never").IgnoreCase);
        }
        #endregion

        #region Equality Tests
        [Test]
        public void EqualityTests()
        {
            int[] i3 = new int[] { 1, 2, 3 };
            double[] d3 = new double[] { 1.0, 2.0, 3.0 };
            int[] iunequal = new int[] { 1, 3, 2 };

            // Classic Syntax
            Assert.AreEqual(4, 2 + 2);
            Assert.AreEqual(i3, d3);
            Assert.AreNotEqual(5, 2 + 2);
            Assert.AreNotEqual(i3, iunequal);

            // Constraint Syntax
            Assert.That(2 + 2, Is.EqualTo(4));
            Assert.That(2 + 2 == 4);
            Assert.That(i3, Is.EqualTo(d3));
            Assert.That(2 + 2, Is.Not.EqualTo(5));
            Assert.That(i3, Is.Not.EqualTo(iunequal));

            // Inherited syntax
            Expect(2 + 2, EqualTo(4));
            Expect(2 + 2 == 4);
            Expect(i3, EqualTo(d3));
            Expect(2 + 2, Not.EqualTo(5));
            Expect(i3, Not.EqualTo(iunequal));
        }

        [Test]
        public void EqualityTestsWithTolerance()
        {
            // CLassic syntax
            Assert.AreEqual(5.0d, 4.99d, 0.05d);
            Assert.AreEqual(5.0f, 4.99f, 0.05f);

            // Constraint Syntax
            Assert.That(4.99d, Is.EqualTo(5.0d).Within(0.05d));
            Assert.That(4.0d, Is.Not.EqualTo(5.0d).Within(0.5d));
            Assert.That(4.99f, Is.EqualTo(5.0f).Within(0.05f));
            Assert.That(4.99m, Is.EqualTo(5.0m).Within(0.05m));
            Assert.That(3999999999u, Is.EqualTo(4000000000u).Within(5u));
            Assert.That(499, Is.EqualTo(500).Within(5));
            Assert.That(4999999999L, Is.EqualTo(5000000000L).Within(5L));
            Assert.That(5999999999ul, Is.EqualTo(6000000000ul).Within(5ul));

            // Inherited syntax
            Expect(4.99d, EqualTo(5.0d).Within(0.05d));
            Expect(4.0d, Not.EqualTo(5.0d).Within(0.5d));
            Expect(4.99f, EqualTo(5.0f).Within(0.05f));
            Expect(4.99m, EqualTo(5.0m).Within(0.05m));
            Expect(499u, EqualTo(500u).Within(5u));
            Expect(499, EqualTo(500).Within(5));
            Expect(4999999999L, EqualTo(5000000000L).Within(5L));
            Expect(5999999999ul, EqualTo(6000000000ul).Within(5ul));
        }

        [Test]
        public void EqualityTestsWithTolerance_MixedFloatAndDouble()
        {
            // Bug Fix 1743844
            Assert.That(2.20492d, Is.EqualTo(2.2d).Within(0.01f),
                "Double actual, Double expected, Single tolerance");
            Assert.That(2.20492d, Is.EqualTo(2.2f).Within(0.01d),
                "Double actual, Single expected, Double tolerance");
            Assert.That(2.20492d, Is.EqualTo(2.2f).Within(0.01f),
                "Double actual, Single expected, Single tolerance");
            Assert.That(2.20492f, Is.EqualTo(2.2f).Within(0.01d),
                "Single actual, Single expected, Double tolerance");
            Assert.That(2.20492f, Is.EqualTo(2.2d).Within(0.01d),
                "Single actual, Double expected, Double tolerance");
            Assert.That(2.20492f, Is.EqualTo(2.2d).Within(0.01f),
                "Single actual, Double expected, Single tolerance");
        }

        [Test]
        public void EqualityTestsWithTolerance_MixingTypesGenerally()
        {
            // Extending tolerance to all numeric types
            Assert.That(202d, Is.EqualTo(200d).Within(2),
                "Double actual, Double expected, int tolerance");
            Assert.That(4.87m, Is.EqualTo(5).Within(.25),
                "Decimal actual, int expected, Double tolerance");
            Assert.That(4.87m, Is.EqualTo(5ul).Within(1),
                "Decimal actual, ulong expected, int tolerance");
            Assert.That(487, Is.EqualTo(500).Within(25),
                "int actual, int expected, int tolerance");
            Assert.That(487u, Is.EqualTo(500).Within(25),
                "uint actual, int expected, int tolerance");
            Assert.That(487L, Is.EqualTo(500).Within(25),
                "long actual, int expected, int tolerance");
            Assert.That(487ul, Is.EqualTo(500).Within(25),
                "ulong actual, int expected, int tolerance");
        }
        #endregion

        #region Comparison Tests
        [Test]
        public void ComparisonTests()
        {
            // Classic Syntax
            Assert.Greater(7, 3);
            Assert.GreaterOrEqual(7, 3);
            Assert.GreaterOrEqual(7, 7);

            // Constraint Syntax
            Assert.That(7, Is.GreaterThan(3));
            Assert.That(7, Is.GreaterThanOrEqualTo(3));
            Assert.That(7, Is.AtLeast(3));
            Assert.That(7, Is.GreaterThanOrEqualTo(7));
            Assert.That(7, Is.AtLeast(7));

            // Inherited syntax
            Expect(7, GreaterThan(3));
            Expect(7, GreaterThanOrEqualTo(3));
            Expect(7, AtLeast(3));
            Expect(7, GreaterThanOrEqualTo(7));
            Expect(7, AtLeast(7));

            // Classic syntax
            Assert.Less(3, 7);
            Assert.LessOrEqual(3, 7);
            Assert.LessOrEqual(3, 3);

            // Constraint Syntax
            Assert.That(3, Is.LessThan(7));
            Assert.That(3, Is.LessThanOrEqualTo(7));
            Assert.That(3, Is.AtMost(7));
            Assert.That(3, Is.LessThanOrEqualTo(3));
            Assert.That(3, Is.AtMost(3));

            // Inherited syntax
            Expect(3, LessThan(7));
            Expect(3, LessThanOrEqualTo(7));
            Expect(3, AtMost(7));
            Expect(3, LessThanOrEqualTo(3));
            Expect(3, AtMost(3));
        }
        #endregion

        #region Collection Tests
        [Test]
        public void AllItemsTests()
        {
            object[] ints = new object[] { 1, 2, 3, 4 };
            object[] doubles = new object[] { 0.99, 2.1, 3.0, 4.05 };
            object[] strings = new object[] { "abc", "bad", "cab", "bad", "dad" };

            // Classic syntax
            CollectionAssert.AllItemsAreNotNull(ints);
            CollectionAssert.AllItemsAreInstancesOfType(ints, typeof(int));
            CollectionAssert.AllItemsAreInstancesOfType(strings, typeof(string));
            CollectionAssert.AllItemsAreUnique(ints);

            // Constraint Syntax
            Assert.That(ints, Is.All.Not.Null);
            Assert.That(ints, Has.None.Null);
            Assert.That(ints, Is.All.InstanceOf(typeof(int)));
            Assert.That(ints, Has.All.InstanceOf(typeof(int)));
            Assert.That(strings, Is.All.InstanceOf(typeof(string)));
            Assert.That(strings, Has.All.InstanceOf(typeof(string)));
            Assert.That(ints, Is.Unique);
            // Only available using new syntax
            Assert.That(strings, Is.Not.Unique);
            Assert.That(ints, Is.All.GreaterThan(0));
            Assert.That(ints, Has.All.GreaterThan(0));
            Assert.That(ints, Has.None.LessThanOrEqualTo(0));
            Assert.That(strings, Is.All.Contains("a"));
            Assert.That(strings, Has.All.Contains("a"));
            Assert.That(strings, Has.Some.StartsWith("ba"));
            Assert.That(strings, Has.Some.Property("Length").EqualTo(3));
            Assert.That(strings, Has.Some.StartsWith("BA").IgnoreCase);
            Assert.That(doubles, Has.Some.EqualTo(1.0).Within(.05));

            // Inherited syntax
            Expect(ints, All.Not.Null);
            Expect(ints, None.Null);
            Expect(ints, All.InstanceOf(typeof(int)));
            Expect(strings, All.InstanceOf(typeof(string)));
            Expect(ints, Unique);
            // Only available using new syntax
            Expect(strings, Not.Unique);
            Expect(ints, All.GreaterThan(0));
            Expect(ints, None.LessThanOrEqualTo(0));
            Expect(strings, All.Contains("a"));
            Expect(strings, Some.StartsWith("ba"));
            Expect(strings, Some.StartsWith("BA").IgnoreCase);
            Expect(doubles, Some.EqualTo(1.0).Within(.05));
        }

        [Test]
        public void SomeItemTests()
        {
            object[] mixed = new object[] { 1, 2, "3", null, "four", 100 };
            object[] strings = new object[] { "abc", "bad", "cab", "bad", "dad" };

            // Not available using the classic syntax

            // Constraint Syntax
            Assert.That(mixed, Has.Some.Null);
            Assert.That(mixed, Has.Some.InstanceOf(typeof(int)));
            Assert.That(mixed, Has.Some.InstanceOf(typeof(string)));
            Assert.That(strings, Has.Some.StartsWith("ba"));
            Assert.That(strings, Has.Some.Not.StartsWith("ba"));

            // Inherited syntax
            Expect(mixed, Some.Null);
            Expect(mixed, Some.InstanceOf(typeof(int)));
            Expect(mixed, Some.InstanceOf(typeof(string)));
            Expect(strings, Some.StartsWith("ba"));
            Expect(strings, Some.Not.StartsWith("ba"));
        }

        [Test]
        public void NoItemTests()
        {
            object[] ints = new object[] { 1, 2, 3, 4, 5 };
            object[] strings = new object[] { "abc", "bad", "cab", "bad", "dad" };

            // Not available using the classic syntax

            // Constraint Syntax
            Assert.That(ints, Has.None.Null);
            Assert.That(ints, Has.None.InstanceOf(typeof(string)));
            Assert.That(ints, Has.None.GreaterThan(99));
            Assert.That(strings, Has.None.StartsWith("qu"));

            // Inherited syntax
            Expect(ints, None.Null);
            Expect(ints, None.InstanceOf(typeof(string)));
            Expect(ints, None.GreaterThan(99));
            Expect(strings, None.StartsWith("qu"));
        }

        [Test]
        public void CollectionContainsTests()
        {
            int[] iarray = new int[] { 1, 2, 3 };
            string[] sarray = new string[] { "a", "b", "c" };

            // Classic syntax
            Assert.Contains(3, iarray);
            Assert.Contains("b", sarray);
            CollectionAssert.Contains(iarray, 3);
            CollectionAssert.Contains(sarray, "b");
            CollectionAssert.DoesNotContain(sarray, "x");
            // Showing that Contains uses NUnit equality
            CollectionAssert.Contains(iarray, 1.0d);

            // Constraint Syntax
            Assert.That(iarray, Has.Member(3));
            Assert.That(sarray, Has.Member("b"));
            Assert.That(sarray, Has.No.Member("x"));
            // Showing that Contains uses NUnit equality
            Assert.That(iarray, Has.Member(1.0d));

            // Only available using the new syntax
            // Note that EqualTo and SameAs do NOT give
            // identical results to Contains because 
            // Contains uses Object.Equals()
            Assert.That(iarray, Has.Some.EqualTo(3));
            Assert.That(iarray, Has.Member(3));
            Assert.That(sarray, Has.Some.EqualTo("b"));
            Assert.That(sarray, Has.None.EqualTo("x"));
            Assert.That(iarray, Has.None.SameAs(1.0d));
            Assert.That(iarray, Has.All.LessThan(10));
            Assert.That(sarray, Has.All.Length.EqualTo(1));
            Assert.That(sarray, Has.None.Property("Length").GreaterThan(3));

            // Inherited syntax
            Expect(iarray, Contains(3));
            Expect(sarray, Contains("b"));
            Expect(sarray, Not.Contains("x"));

            // Only available using new syntax
            // Note that EqualTo and SameAs do NOT give
            // identical results to Contains because 
            // Contains uses Object.Equals()
            Expect(iarray, Some.EqualTo(3));
            Expect(sarray, Some.EqualTo("b"));
            Expect(sarray, None.EqualTo("x"));
            Expect(iarray, All.LessThan(10));
            Expect(sarray, All.Length.EqualTo(1));
            Expect(sarray, None.Property("Length").GreaterThan(3));
        }

        [Test]
        public void CollectionEquivalenceTests()
        {
            int[] ints1to5 = new int[] { 1, 2, 3, 4, 5 };
            int[] twothrees = new int[] { 1, 2, 3, 3, 4, 5 };
            int[] twofours = new int[] { 1, 2, 3, 4, 4, 5 };

            // Classic syntax
            CollectionAssert.AreEquivalent(new int[] { 2, 1, 4, 3, 5 }, ints1to5);
            CollectionAssert.AreNotEquivalent(new int[] { 2, 2, 4, 3, 5 }, ints1to5);
            CollectionAssert.AreNotEquivalent(new int[] { 2, 4, 3, 5 }, ints1to5);
            CollectionAssert.AreNotEquivalent(new int[] { 2, 2, 1, 1, 4, 3, 5 }, ints1to5);
            CollectionAssert.AreNotEquivalent(twothrees, twofours);

            // Constraint Syntax
            Assert.That(new int[] { 2, 1, 4, 3, 5 }, Is.EquivalentTo(ints1to5));
            Assert.That(new int[] { 2, 2, 4, 3, 5 }, Is.Not.EquivalentTo(ints1to5));
            Assert.That(new int[] { 2, 4, 3, 5 }, Is.Not.EquivalentTo(ints1to5));
            Assert.That(new int[] { 2, 2, 1, 1, 4, 3, 5 }, Is.Not.EquivalentTo(ints1to5));

            // Inherited syntax
            Expect(new int[] { 2, 1, 4, 3, 5 }, EquivalentTo(ints1to5));
            Expect(new int[] { 2, 2, 4, 3, 5 }, Not.EquivalentTo(ints1to5));
            Expect(new int[] { 2, 4, 3, 5 }, Not.EquivalentTo(ints1to5));
            Expect(new int[] { 2, 2, 1, 1, 4, 3, 5 }, Not.EquivalentTo(ints1to5));
        }

        [Test]
        public void SubsetTests()
        {
            int[] ints1to5 = new int[] { 1, 2, 3, 4, 5 };

            // Classic syntax
            CollectionAssert.IsSubsetOf(new int[] { 1, 3, 5 }, ints1to5);
            CollectionAssert.IsSubsetOf(new int[] { 1, 2, 3, 4, 5 }, ints1to5);
            CollectionAssert.IsNotSubsetOf(new int[] { 2, 4, 6 }, ints1to5);
            CollectionAssert.IsNotSubsetOf(new int[] { 1, 2, 2, 2, 5 }, ints1to5);

            // Constraint Syntax
            Assert.That(new int[] { 1, 3, 5 }, Is.SubsetOf(ints1to5));
            Assert.That(new int[] { 1, 2, 3, 4, 5 }, Is.SubsetOf(ints1to5));
            Assert.That(new int[] { 2, 4, 6 }, Is.Not.SubsetOf(ints1to5));

            // Inherited syntax
            Expect(new int[] { 1, 3, 5 }, SubsetOf(ints1to5));
            Expect(new int[] { 1, 2, 3, 4, 5 }, SubsetOf(ints1to5));
            Expect(new int[] { 2, 4, 6 }, Not.SubsetOf(ints1to5));
        }
        #endregion

        #region Property Tests
        [Test]
        public void PropertyTests()
        {
            string[] array = { "abc", "bca", "xyz", "qrs" };
            string[] array2 = { "a", "ab", "abc" };
            ArrayList list = new ArrayList(array);

            // Not available using the classic syntax

            // Constraint Syntax
            Assert.That(list, Has.Property("Count"));
            Assert.That(list, Has.No.Property("Length"));

            Assert.That("Hello", Has.Length.EqualTo(5));
            Assert.That("Hello", Has.Length.LessThan(10));
            Assert.That("Hello", Has.Property("Length").EqualTo(5));
            Assert.That("Hello", Has.Property("Length").GreaterThan(3));

            Assert.That(array, Has.Property("Length").EqualTo(4));
            Assert.That(array, Has.Length.EqualTo(4));
            Assert.That(array, Has.Property("Length").LessThan(10));

            Assert.That(array, Has.All.Property("Length").EqualTo(3));
            Assert.That(array, Has.All.Length.EqualTo(3));
            Assert.That(array, Is.All.Length.EqualTo(3));
            Assert.That(array, Has.All.Property("Length").EqualTo(3));
            Assert.That(array, Is.All.Property("Length").EqualTo(3));

            Assert.That(array2, Has.Some.Property("Length").EqualTo(2));
            Assert.That(array2, Has.Some.Length.EqualTo(2));
            Assert.That(array2, Has.Some.Property("Length").GreaterThan(2));

            Assert.That(array2, Is.Not.Property("Length").EqualTo(4));
            Assert.That(array2, Is.Not.Length.EqualTo(4));
            Assert.That(array2, Has.No.Property("Length").GreaterThan(3));

            Assert.That(List.Map(array2).Property("Length"), Is.EqualTo(new int[] { 1, 2, 3 }));
            Assert.That(List.Map(array2).Property("Length"), Is.EquivalentTo(new int[] { 3, 2, 1 }));
            Assert.That(List.Map(array2).Property("Length"), Is.SubsetOf(new int[] { 1, 2, 3, 4, 5 }));
            Assert.That(List.Map(array2).Property("Length"), Is.Unique);

            Assert.That(list, Has.Count.EqualTo(4));

            // Inherited syntax
            Expect(list, Property("Count"));
            Expect(list, Not.Property("Nada"));

            Expect("Hello", Length.EqualTo(5));
            Expect("Hello", Property("Length").EqualTo(5));
            Expect("Hello", Property("Length").GreaterThan(0));

            Expect(array, Property("Length").EqualTo(4));
            Expect(array, Length.EqualTo(4));
            Expect(array, Property("Length").LessThan(10));

            Expect(array, All.Length.EqualTo(3));
            Expect(array, All.Property("Length").EqualTo(3));

            Expect(array2, Some.Property("Length").EqualTo(2));
            Expect(array2, Some.Length.EqualTo(2));
            Expect(array2, Some.Property("Length").GreaterThan(2));

            Expect(array2, None.Property("Length").EqualTo(4));
            Expect(array2, None.Length.EqualTo(4));
            Expect(array2, None.Property("Length").GreaterThan(3));

            Expect(Map(array2).Property("Length"), EqualTo(new int[] { 1, 2, 3 }));
            Expect(Map(array2).Property("Length"), EquivalentTo(new int[] { 3, 2, 1 }));
            Expect(Map(array2).Property("Length"), SubsetOf(new int[] { 1, 2, 3, 4, 5 }));
            Expect(Map(array2).Property("Length"), Unique);

            Expect(list, Count.EqualTo(4));

        }
        #endregion

        #region Not Tests
        [Test]
        public void NotTests()
        {
            // Not available using the classic syntax

            // Constraint Syntax
            Assert.That(42, Is.Not.Null);
            Assert.That(42, Is.Not.True);
            Assert.That(42, Is.Not.False);
            Assert.That(2.5, Is.Not.NaN);
            Assert.That(2 + 2, Is.Not.EqualTo(3));
            Assert.That(2 + 2, Is.Not.Not.EqualTo(4));
            Assert.That(2 + 2, Is.Not.Not.Not.EqualTo(5));

            // Inherited syntax
            Expect(42, Not.Null);
            Expect(42, Not.True);
            Expect(42, Not.False);
            Expect(2.5, Not.NaN);
            Expect(2 + 2, Not.EqualTo(3));
            Expect(2 + 2, Not.Not.EqualTo(4));
            Expect(2 + 2, Not.Not.Not.EqualTo(5));
        }
        #endregion

        #region Operator Tests
        [Test]
        public void NotOperator()
        {
            // The ! operator is only available in the new syntax
            Assert.That(42, !Is.Null);
            // Inherited syntax
            Expect(42, !Null);
        }

        [Test]
        public void AndOperator()
        {
            // The & operator is only available in the new syntax
            Assert.That(7, Is.GreaterThan(5) & Is.LessThan(10));
            // Inherited syntax
            Expect(7, GreaterThan(5) & LessThan(10));
        }

        [Test]
        public void OrOperator()
        {
            // The | operator is only available in the new syntax
            Assert.That(3, Is.LessThan(5) | Is.GreaterThan(10));
            Expect(3, LessThan(5) | GreaterThan(10));
        }

        [Test]
        public void ComplexTests()
        {
            Assert.That(7, Is.Not.Null & Is.Not.LessThan(5) & Is.Not.GreaterThan(10));
            Expect(7, Not.Null & Not.LessThan(5) & Not.GreaterThan(10));

            Assert.That(7, !Is.Null & !Is.LessThan(5) & !Is.GreaterThan(10));
            Expect(7, !Null & !LessThan(5) & !GreaterThan(10));

            // No longer works at all under 3.0
            // TODO: Evaluate why we wanted to use null in this setting in the first place
#if false
                // TODO: Remove #if when mono compiler can handle null
#if MONO
                Constraint x = null;
                Assert.That(7, !x & !Is.LessThan(5) & !Is.GreaterThan(10));
                Expect(7, !x & !LessThan(5) & !GreaterThan(10));
#else
                Assert.That(7, !(Constraint)null & !Is.LessThan(5) & !Is.GreaterThan(10));
                Expect(7, !(Constraint)null & !LessThan(5) & !GreaterThan(10));
#endif
#endif
        }
        #endregion

        #region Invalid Code Tests
        // This method contains assertions that should not compile
        // You can check by uncommenting it.
        //public void WillNotCompile()
        //{
        //    Assert.That(42, Is.Not);
        //    Assert.That(42, Is.All);
        //    Assert.That(42, Is.Null.Not);
        //    Assert.That(42, Is.Not.Null.GreaterThan(10));
        //    Assert.That(42, Is.GreaterThan(10).LessThan(99));

        //    object[] c = new object[0];
        //    Assert.That(c, Is.Null.All);
        //    Assert.That(c, Is.Not.All);
        //    Assert.That(c, Is.All.Not);
        //}
        #endregion
    }

#endregion

单元测试参考资料

• MSDN - Microsoft.VisualStudio.TestTools.UnitTesting
• 单元测试之道
• VS2012 Unit Test 个人学习汇总（含目录）
• 单元测试的优点
• 对比MS Test与NUnit Test框架