测试装置示例
    请考虑以下针对 BankAccount 类的类关系图，以及一个示例测试装置 (BankAccountTests.cs)。

    图 1. BankAccount 类

    示例测试装置： BankAccountTests.cs
using BankAccountDemo.Business;
using Microsoft.VisualStudio.QualityTools.UnitTesting.Framework;
namespace BankAccountDemo.Business.Tests
{
    [TestClass()]
    public class BankAccountTest
    {
        [TestInitialize()]
        public void Initialize()    {
        }
        [TestCleanup()]
        public void Cleanup()   {
        }
        [TestMethod()]
        public void ConstructorTest()   {
            float currentBalance = 500;
            BankAccount target = new BankAccount(currentBalance);
            Assert.AreEqual(currentBalance, target.CurrentBalance,
                "Balances are not equal upon creation");
        }
        [TestMethod()]
        public void DepositMoneyTest()  {
            float currentBalance = 500;
            BankAccount target = new BankAccount(currentBalance);
            float depositAmount = 10;
            target.DepositMoney(depositAmount);
            Assert.IsTrue( (currentBalance + depositAmount) > 
                            target.CurrentBalance,
               "Deposit not applied correctly");
        }
        [TestMethod()]
        public void MakePaymentTest()   {
            float currentBalance = 500;
            BankAccount target = new BankAccount(currentBalance);
            float paymentAmount = 250;
            target.MakePayment(paymentAmount);
            Assert.IsTrue(currentBalance - paymentAmount ==
              target.CurrentBalance,
                "Payment not applied correctly");
        }
    }
}

    主单元测试概念 == 断言
    用于该形式单元测试的主要概念是，自动化单元测试是基于“断言”的，即可定义为“事实或您相信为事实的内容”。从逻辑角度看，请考虑该语句“when I do {x}, I expect {y} as a result”。

   这可以轻松地翻译为代码，方法是使用 Microsoft.VisualStudio.QualityTools.UnitTesting.Framework 命名空间中可用的三个“断言”类中的任一个：Assert、StringAssert 和 CollectionAssert。主类 Assert 提供用于测试基础条件语句的断言。StringAssert 类自定义了在使用字符串变量时有用的断言。同样，CollectionAssert 类包括在使用对象集合时有用的断言方法。

    表 3 显示可用于当前版本 Unit Testing Framework 的断言。

    表 3. VSTS Unit Testing Framework 断言
断言类 StringAssert 类 CollectionAssert 类
AreEqual()
AreNotEqual()
AreNotSame()
AreSame()
EqualsTests()
Fail()
GetHashCodeTests()
Inconclusive()
IsFalse()
IsInstanceOfType()
IsNotInstanceOfType()
IsNotNull()
IsNull()
IsTrue()

 Contains()
DoesNotMatch()
EndsWith()
Matches()
StartsWith()

 AllItemsAreInstancesOfType()
AllItemsAreNotNull()
AllItemsAreUnique()
AreEqual()
AreEquivalent()
AreNotEqual()
AreNotEquivalent()
Contains()
DoesNotContain()
IsNotSubsetOf()
IsSubsetOf()