第一部分: http://www.cnblogs.com/cgzl/p/8283610.html
下面有一点点内容是重叠的....
String Assert
测试string是否相等：
???????[Fact] ???????public void CalculateFullName() ???????{ ???????????var p = new Patient ???????????{ ???????????????FirstName = "Nick", ???????????????LastName = "Carter" ???????????}; ???????????Assert.Equal("Nick Carter", p.FullName); ???????}然后你需要Build一下，这样VS Test Explorer才能发现新的test。
运行测试，结果Pass：
同样改一下Patient类（别忘了Build一下），让结果失败：
从失败信息可以看到期待值和实际值。
StartsWith, EndsWith
???????[Fact] ???????public void CalculateFullNameStartsWithFirstName() ???????{ ???????????var p = new Patient ???????????{ ???????????????FirstName = "Nick", ???????????????LastName = "Carter" ???????????}; ???????????Assert.StartsWith("Nick", p.FullName); ???????} ???????[Fact] ???????public void CalculateFullNameEndsWithFirstName() ???????{ ???????????var p = new Patient ???????????{ ???????????????FirstName = "Nick", ???????????????LastName = "Carter" ???????????}; ???????????Assert.EndsWith("Carter", p.FullName);e); ???????}Build，然后Run Test，结果Pass：
忽略大小写 ignoreCase：
string默认的Assert是区分大小写的，这样就会失败：
可以为这些方法添加一个参数ignoreCase设置为true，就会忽略大小写：
包含子字符串 Contains
???????[Fact] ???????public void CalculateFullNameSubstring() ???????{ ???????????var p = new Patient ???????????{ ???????????????FirstName = "Nick", ???????????????LastName = "Carter" ???????????}; ???????????Assert.Contains("ck Ca", p.FullName); ???????}Build，测试结果Pass。
正则表达式，Matches
测试一下First name和Last name的首字母是不是大写的：
???????[Fact] ???????public void CalculcateFullNameWithTitleCase() ???????{ ???????????var p = new Patient ???????????{ ???????????????FirstName = "Nick", ???????????????LastName = "Carter" ???????????}; ???????????Assert.Matches("[A-Z]{1}{a-z}+ [A-Z]{1}[a-z]+", p.FullName); ???????}Build，测试通过。
数值 Assert
首先为Patient类添加一个property： BloodSugar。
???public class Patient ???{ ???????public Patient() ???????{ ???????????IsNew = true; ???????????_bloodSugar = 5.0f; ???????} ???????private float _bloodSugar; ???????public float BloodSugar ???????{ ???????????get { return _bloodSugar; } ???????????set { _bloodSugar = value; } ???????} ???????...Equal:
???????[Fact] ???????public void BloodSugarStartWithDefaultValue() ???????{ ???????????var p = new Patient(); ???????????Assert.Equal(5.0, p.BloodSugar); ???????}Build，测试通过。
范围， InRange:
首先为Patient类添加一个方法，病人吃饭之后血糖升高：
???????public void HaveDinner() ???????{ ???????????var random = new Random(); ???????????_bloodSugar += (float)random.Next(1, 1000) / 100; // ?应该是1000 ???????}添加test：
???????[Fact] ???????public void BloodSugarIncreaseAfterDinner() ???????{ ???????????var p = new Patient(); ???????????p.HaveDinner(); ???????????// Assert.InRange<float>(p.BloodSugar, 5, 6); ???????????Assert.InRange(p.BloodSugar, 5, 6); ???????}Build，Run Test，结果Fail：
可以看到期待的Range和实际的值，这样很好。如果你使用Assert.True(xx >= 5 && xx <= 6)的话，错误信息只能显示True或者False。
因为HaveDinner方法里，表达式的分母应该是1000，修改后，Build，Run，测试Pass。
浮点型数值的Assert
在被测项目添加这两个类:
namespace Hospital{ ???public abstract class Worker ???{ ???????public string Name { get; set; } ???????public abstract double TotalReward { get; } ???????public abstract double Hours { get; } ???????public double Salary => TotalReward / Hours; ???} ???public class Plumber : Worker ???{ ???????public override double TotalReward => 200; ???????public override double Hours => 3; ???}}然后针对Plumber建立一个测试类 PlumberShould.cs, 并建立第一个test:
namespace Hospital.Tests{ ???public class PlumberShould ???{ ???????[Fact] ???????public void HaveCorrectSalary() ???????{ ???????????var plumber = new Plumber(); ???????????Assert.Equal(66.666, plumber.Salary); ???????} ???}}Build项目, 然后再Test Explorer里面选择按Class分类显示Tests:
Run Selected Test, 结果会失败:
这是一个精度的问题.
在Assert.Equal方法, 可以添加一个precision参数, 设置精度为3:
???????[Fact] ???????public void HaveCorrectSalary() ???????{ ???????????var plumber = new Plumber(); ???????????Assert.Equal(66.666, plumber.Salary, precision: 3); ???????}Build, Run Test:
因为有四舍五入的问题, 所以test仍然fail了.
所以还需要改一下:
???????[Fact] ???????public void HaveCorrectSalary() ???????{ ???????????var plumber = new Plumber(); ???????????Assert.Equal(66.667, plumber.Salary, precision: 3); ???????}这次会pass的:
Assert Null值
???????[Fact] ???????public void NotHaveNameByDefault() ???????{ ???????????var plumber = new Plumber(); ???????????Assert.Null(plumber.Name); ???????} ???????[Fact] ???????public void HaveNameValue() ???????{ ???????????var plumber = new Plumber ???????????{ ???????????????Name = "Brian" ???????????}; ???????????Assert.NotNull(plumber.Name); ???????}有两个方法, Assert.Null 和 Assert.NotNull, 直接传入期待即可.
测试会Pass的.
集合 Collection Assert
修改一下被测试类, 添加一个集合属性, 并赋值:
namespace Hospital{ ???public abstract class Worker ???{ ???????public string Name { get; set; } ???????public abstract double TotalReward { get; } ???????public abstract double Hours { get; } ???????public double Salary => TotalReward / Hours; ???????public List<string> Tools { get; set; } ???} ???public class Plumber : Worker ???{ ???????public Plumber() ???????{ ???????????Tools = new List<string>() ???????????{ ???????????????"螺丝刀", ???????????????"扳子", ???????????????"钳子" ???????????}; ???????} ???????public override double TotalReward => 200; ???????public override double Hours => 3; ???}}测试是否包含某个元素, Assert.Contains():
???????[Fact] ???????public void HaveScrewdriver() ???????{ ???????????var plumber = new Plumber(); ???????????Assert.Contains("螺丝刀", plumber.Tools); ???????}Build, Run Test, 结果Pass.
修改一下名字, 让其Fail:
这个失败信息还是很详细的.
相应的还有一个Assert.DoesNotContain()方法, 测试集合是否不包含某个元素.
???????[Fact] ???????public void NotHaveKeyboard() ???????{ ???????????var plumber = new Plumber(); ???????????Assert.DoesNotContain("键盘", plumber.Tools); ???????}这个test也会pass.
Predicate:
测试一下集合中是否包含符合某个条件的元素:
???????[Fact] ???????public void HaveAtLeastOneScrewdriver() ???????{ ???????????var plumber = new Plumber(); ???????????Assert.Contains(plumber.Tools, t => t.Contains("螺丝刀")); ???????}使用的是Assert.Contains的一个overload方法, 它的第一个参数是集合, 第二个参数是Predicate.
Build, Run Test, 会Pass的.
比较集合相等:
添加Test:
???????[Fact] ???????public void HaveAllTools() ???????{ ???????????var plumber = new Plumber(); ???????????var expectedTools = new [] ???????????{ ???????????????"螺丝刀", ???????????????"扳子", ???????????????"钳子" ???????????}; ???????????Assert.Equal(expectedTools, plumber.Tools); ???????}注意, Plumber的tools类型是List, 这里的expectedTools类型是array.
这个test 仍然会Pass.
如果修改一个元素, 那么测试会Fail, 信息如下:
Assert针对集合的每个元素:
如果想对集合的每个元素进行Assert, 当然可以通过循环来Assert了, 但是更好的写法是调用Assert.All()方法:
???????[Fact] ???????public void HaveNoEmptyDefaultTools() ???????{ ???????????var plumber = new Plumber(); ???????????Assert.All(plumber.Tools, t => Assert.False(string.IsNullOrEmpty(t))); ???????}这个测试会Pass.
如果在被测试类的Tools属性添加一个空字符串, 那么失败信息会是:
这里写到, 4个元素里面有1个没有pass.
针对Object类型的Assert
首先再添加一个Programmer类:
???public class Programmer : Worker ???{ ???????public override double TotalReward => 1000; ???????public override double Hours => 3.5; ???}然后建立一个WorkerFactory:
namespace Hospital{ ???public class WorkerFactory ???{ ???????public Worker Create(string name, bool isProgrammer = false) ???????{ ???????????if (isProgrammer) ???????????{ ???????????????return new Programmer { Name = name }; ???????????} ???????????return new Plumber { Name = name }; ???????} ???}}判断是否是某个类型 Assert.IsType<Type>(xx):
建立一个测试类 WorkerShould.cs和一个test:
namespace Hospital.Tests{ ???public class WorkerShould ???{ ???????[Fact] ???????public void CreatePlumberByDefault() ???????{ ???????????var factory = new WorkerFactory(); ???????????Worker worker = factory.Create("Nick"); ???????????Assert.IsType<Plumber>(worker); ???????} ???}}Build, Run Test: 结果Pass.
相应的, 还有一个Assert.IsNotType<Type>(xx)方法.
利用Assert.IsType<Type>(xx)的返回值, 它会返回Type(xx的)的这个实例, 添加个一test:
???????[Fact] ???????public void CreateProgrammerAndCastReturnedType() ???????{ ???????????var factory = new WorkerFactory(); ???????????Worker worker = factory.Create("Nick", isProgrammer: true); ???????????Programmer programmer = Assert.IsType<Programmer>(worker); ???????????Assert.Equal("Nick", programmer.Name); ???????}Build, Run Tests: 结果Pass.
Assert针对父类:
写这样一个test, 创建的是一个promgrammer, Assert的类型是它的父类Worker:
???????[Fact] ???????public void CreateProgrammer_AssertAssignableTypes() ???????{ ???????????var factory = new WorkerFactory(); ???????????Worker worker = factory.Create("Nick", isProgrammer: true); ???????????Assert.IsType<Worker>(worker); ???????}这个会Fail:
这时就应该使用这个方法, Assert.IsAssignableFrom<祖先类>(xx):
???????[Fact] ???????public void CreateProgrammer_AssertAssignableTypes() ???????{ ???????????var factory = new WorkerFactory(); ???????????Worker worker = factory.Create("Nick", isProgrammer: true); ???????????Assert.IsAssignableFrom<Worker>(worker); ???????}Build, Run Tests: Pass.
Assert针对对象的实例
判断两个引用是否指向不同的实例 Assert.NotSame(a, b):
???????[Fact] ???????public void CreateSeperateInstances() ???????{ ???????????var factory = new WorkerFactory(); ???????????var p1 = factory.Create("Nick"); ???????????var p2 = factory.Create("Nick"); ???????????Assert.NotSame(p1, p2); ???????}由工厂创建的两个对象是不同的实例, 所以这个test会Pass.
相应的还有个Assert.Same(a, b) 方法.
Assert 异常
为WorkFactory先添加一个异常处理:
namespace Hospital{ ???public class WorkerFactory ???{ ???????public Worker Create(string name, bool isProgrammer = false) ???????{ ???????????if (name == null) ???????????{ ???????????????throw new ArgumentNullException(nameof(name)); ???????????} ???????????if (isProgrammer) ???????????{ ???????????????return new Programmer { Name = name }; ???????????} ???????????return new Plumber { Name = name }; ???????} ???}}如果在test执行代码时抛出异常的话, 那么test会直接fail掉.
所以应该使用Assert.Throws<ArgumentNullException>(...)方法来Assert是否抛出了特定类型的异常.
添加一个test:
???????[Fact] ???????public void NotAllowNullName() ???????{ ???????????var factory = new WorkerFactory();
???????????// var p = factory.Create(null); // 这个会失败 ???????????Assert.Throws<ArgumentNullException>(() => factory.Create(null)); ???????}注意不要直接运行会抛出异常的代码. 应该在Assert.Throws<ET>()的方法里添加lambda表达式来调用方法.
这样的话就会pass.
如果被测试代码没有抛出异常的话, 那么test会fail的. 把抛异常代码注释掉之后再Run:
更具体的, 还可以指定参数的名称:
???????[Fact] ???????public void NotAllowNullName() ???????{ ???????????var factory = new WorkerFactory(); ???????????// Assert.Throws<ArgumentNullException>(() => factory.Create(null)); ???????????Assert.Throws<ArgumentNullException>("name", () => factory.Create(null)); ???????}这里就是说异常里应该有一个叫name的参数.
Run: Pass.
如果把"name"改成"isProgrammer", 那么这个test会fail:
利用Assert.Throws<ET>()的返回结果, 其返回结果就是这个抛出的异常实例.
???????[Fact] ???????public void NotAllowNullNameAndUseReturnedException() ???????{ ???????????var factory = new WorkerFactory(); ???????????ArgumentNullException ex = Assert.Throws<ArgumentNullException>(() => factory.Create(null)); ???????????Assert.Equal("name", ex.ParamName); ???????}Assert Events 是否发生(Raised)
回到之前的Patient类, 添加如下代码:
???????public void Sleep() ???????{ ???????????OnPatientSlept(); ???????} ???????public event EventHandler<EventArgs> PatientSlept; ???????protected virtual void OnPatientSlept() ???????{ ???????????PatientSlept?.Invoke(this, EventArgs.Empty); ???????}然后回到PatientShould.cs添加test:
???????[Fact] ???????public void RaiseSleptEvent() ???????{ ???????????var p = new Patient(); ???????????Assert.Raises<EventArgs>( ???????????????handler => p.PatientSlept += handler, ????????????????handler => p.PatientSlept -= handler, ????????????????() => p.Sleep()); ???????}Assert.Raises<T>()第一个参数是附加handler的Action, 第二个参数是分离handler的Action, 第三个Action是触发event的代码.
Build, Run Test: Pass.
如果注释掉Patient类里Sleep()方法内部那行代码, 那么test会fail:
针对INotifyPropertyChanged的特殊Assert:
修改Patient代码:
namespace Hospital{ ???public class Patient: INotifyPropertyChanged ???{ ???????public Patient() ???????{ ???????????IsNew = true; ???????????_bloodSugar = 5.0f; ???????} ???????public string FirstName { get; set; } ???????public string LastName { get; set; } ???????public string FullName => $"{FirstName} {LastName}"; ???????public int HeartBeatRate { get; set; } ???????public bool IsNew { get; set; } ???????private float _bloodSugar; ???????public float BloodSugar ???????{ ???????????get => _bloodSugar; ???????????set => _bloodSugar = value; ???????} ???????public void HaveDinner() ???????{ ???????????var random = new Random(); ???????????_bloodSugar += (float)random.Next(1, 1000) / 1000; ???????????OnPropertyChanged(nameof(BloodSugar)); ???????} ???????public void IncreaseHeartBeatRate() ???????{ ???????????HeartBeatRate = CalculateHeartBeatRate() + 2; ???????} ???????private int CalculateHeartBeatRate() ???????{ ???????????var random = new Random(); ???????????return random.Next(1, 100); ???????} ???????public void Sleep() ???????{ ???????????OnPatientSlept(); ???????} ???????public event EventHandler<EventArgs> PatientSlept; ???????protected virtual void OnPatientSlept() ???????{ ???????????PatientSlept?.Invoke(this, EventArgs.Empty); ???????} ???????public event PropertyChangedEventHandler PropertyChanged; ???????protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null) ???????{ ???????????PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName)); ???????} ???}}添加一个Test:
???????[Fact] ???????public void RaisePropertyChangedEvent() ???????{ ???????????var p = new Patient(); ???????????Assert.PropertyChanged(p, "BloodSugar", () => p.HaveDinner()); ???????}针对INotifyPropertyChanged, 可以使用Assert.PropertyChanged(..) 这个专用的方法来断定PropertyChanged的Event是否被触发了.
Build, Run Tests: Pass.
到目前为止, 介绍的都是入门级的内容.
接下来要介绍的是稍微进阶一点的内容了.
使用xUnit为.net core程序进行单元测试(中)
原文地址：https://www.cnblogs.com/cgzl/p/8287588.html