单元测试实践

前言

在此，只是对下面这条链接的实现:

https://www.cnblogs.com/AlexanderZhao/p/12369732.html

正文

测试分类:

1.单元测试

2.集成测试

3.皮下测试

4.UI测试

测试的三个阶段：AAA

Arrange: 在这里做一些先决的设定。例如创建对象实例，数据，输入等。

Act: 在这里执行生产代码并返回结果。例如调用方法或者设置属性。

Assert:在这里检查结果，会产生测试通过或者失败两种结果。

Assert方法应用

bool 值:

Patient patient = new Patient();
var result = patient.IsNew;
Assert.True(result);
Assert.False(result);

string 类型:

[Fact]
public async void Test1()
{
	Patient patient = new Patient();
	Assert.Equal("xxx",patient.FistName);
	Assert.NotEqual("xxx",patient.LastName);
	Assert.StartsWith("xxx",patient.LastName);
	Assert.EndsWith("xxx",patient.LastName);
	Assert.Contains("xxx",patient.LastName);
	Assert.Matches(@"xxx",patient.LastName);
}

数字类型:

Patient patient = new Patient();
var result = patient.Age;
Assert.Equal(4.9f,result);
Assert.InRange(result,3.9,6.1);

判断null 和 not null

var p = new Patient();
Assert.Null(p.FirstName);
Assert.NotNull(_patient);

集合:

Patient patient = new Patient();
var diseases = new List<string>
{
	"感冒",
	"发烧",
	"水痘",
	"腹泻"
};
Assert.Contains("感冒",patient.History);
Assert.DoesNotContain("感冒", patient.History);
// any
Assert.Contains(patient.History,x=>x.StartsWith("水"));
// 遍历 all
Assert.All(patient.History, x => { Assert.True(x.Length > 2); });
Assert.Equal(diseases,patient.History);

对象:

Patient patient = new Patient();
Patient patient1 = new Patient();
// 类型是否相同
Assert.IsNotType<Patient>(patient);
Assert.IsType<Patient>(patient);
// 两个实例是否是同一个
Assert.Same(patient,patient1);
Assert.NotSame(patient, patient1);
//是否继承Patient
Assert.IsAssignableFrom<Patient>(patient);

错误性验证:

Patient patient = new Patient();
// 判断是否出现指定的异常
var ex = Assert.Throws<InvalidOperationException>(()=> { patient.NotAllowed(); });
// 进一步判断异常消息
Assert.Equal("not able to create", ex.Message);

判断是否触发事件：

/// <summary>
/// 判断是否触发事件
/// </summary>
[Fact]
public void RaizeSleepEvent()
{
    var p = new Patient();
    Assert.Raises<EventArgs>(
        handler=>p.PatientSlept+=handler,
        handler=>p.PatientSlept -= handler,
        () => p.Sleep());
}

判断属性改变是否触发事件#

/// <summary>
/// 测试属性改变事件是否触发
/// </summary>
[Fact]
public void RaisePropertyChangedEvent()
{
    var p = new Patient();
    Assert.PropertyChanged(p, nameof(p.HeartBeatRate),
                           () => p.IncreaseHeartBeatRate());
}

进阶

分组测试:

[Fact]
[Trait("Category", "New")]
public void BeNewWhenCreated()
{
	var patient = new Patient();
	patient.IsNew = true;
	var result = patient.IsNew;
	Assert.True(result);
}

[Fact]
[Trait("Category", "add")]
public void BeNewWhenCreated1()
{
	var patient = new Patient();
	var result = patient.IsNew;
	Assert.True(result);;
}

dotnet test --filter “Category=New” //运行单个分类测试
dotnet test --filter “Category=New|Category=Add”//运行多个分类测试
dotnet test --filter Category --logger:trx //输出测试日志

忽略测试#

使用特性：[Fact(Skip="不跑这个测试")]，可以忽略测试，忽略测试图标为黄色警告

自定义测试输出内容#

使用ITestOutputHelper可以自定义在测试时的输出内容
dotnet test --filter Category --logger:trx会输出测试日志trx结尾的文件

public class PatientShould:IClassFixture<LongTimeFixture>,IDisposable
{
    private readonly ITestOutputHelper _output;
    private readonly Patient _patient;
    private readonly LongTimeTask _task;
    public PatientShould(ITestOutputHelper output,LongTimeFixture fixture)
    {
        this._output = output;
        _patient = new Patient();
        //_task = new LongTimeTask();
        _task = fixture.Task;
    }

    [Fact]
    [Trait("Category","New")]
    public void BeNewWhenCreated()
    {
        _output.WriteLine("第一个测试");
        // Arrange
        //var patient = new Patient();
        // Act
        var result = _patient.IsNew;
        // Assert
        Assert.True(result);
        //Assert.False(result);
    }
}

减少重复代码#

减少new对象，可以在构造函数中new，在方法中使用。
测试类实现IDispose接口，测试完释放资源，注意每个测试结束后都会调用Dispose方法。

共享上下文#
同一个测试类#

在执行一个方法时，需要很长事件，而在构造函数中new时，每个测试跑的时候都会new对象或者执行方法，这是导致测试很慢。解决方法：

创建一个类：

using Demo2;
using System;

namespace Demo2Test
{
    public class LongTimeFixture : IDisposable
    {
        public LongTimeTask Task { get; }
        public LongTimeFixture()
        {

        }
        public void Dispose()
        {
        }
    }
}

测试类实现IClassFixture接口,并在构造函数中获取方法

public class PatientShould:IClassFixture<LongTimeFixture>,IDisposable
{
    private readonly ITestOutputHelper _output;
    private readonly Patient _patient;
    private readonly LongTimeTask _task;
    public PatientShould(ITestOutputHelper output,LongTimeFixture fixture)
    {
        this._output = output;
        _patient = new Patient();
        //_task = new LongTimeTask();
        _task = fixture.Task;//获取方法
    }
}

不同的测试类#

1.在上一个的继承上，先建立一个TaskCollection类，实现ICollectionFixture接口，注意不能有副作用，否则会影响结果

using Xunit;

namespace Demo2Test
{
    [CollectionDefinition("Lone Time Task Collection")]
    public class TaskCollection:ICollectionFixture<LongTimeFixture>
    {
    }
}

使用，加上[Collection("Lone Time Task Collection")]

[Collection("Lone Time Task Collection")]
public class PatientShould:IClassFixture<LongTimeFixture>,IDisposable
{
    private readonly ITestOutputHelper _output;
    private readonly Patient _patient;
    private readonly LongTimeTask _task;
    public PatientShould(ITestOutputHelper output,LongTimeFixture fixture)
    {
        this._output = output;
        _patient = new Patient();
        //_task = new LongTimeTask();
        _task = fixture.Task;//获取方法
    }
}

数据共享

1. 使用[Theory]，可以写有构造参数的测试方法,使用InlineData传递数据#

[Theory]
[InlineData(1,2,3)]
[InlineData(2,2,4)]
[InlineData(3,3,6)]
public void ShouldAddEquals(int operand1,int operand2,int expected)
{
    //Arrange
    var sut = new Calculator(); //sut-system under test
    //Act
    var result = sut.Add(operand1, operand2);
    //Assert
    Assert.Equal(expected, result);
}

2. 使用[MemberData]特性,可以在多个测试中使用#

先添加CalculatorTestData类：

using System.Collections.Generic;

namespace DemoTest
{
    public  class CalculatorTestData
    {
        private static readonly List<object[]> Data = new List<object[]>
        {
            new object[]{ 1,2,3},
            new object[]{ 1,3,4},
            new object[]{ 2,4,6},
            new object[]{ 0,1,1},
        };

        public static IEnumerable<object[]> TestData => Data;
    }
}

使用MemberData

/// <summary>
/// 数据共享-MemberData
/// </summary>
/// <param name="operand1"></param>
/// <param name="operand2"></param>
/// <param name="expected"></param>
[Theory]
[MemberData(nameof(CalculatorTestData.TestData),MemberType =typeof(CalculatorTestData))]
public void ShouldAddEquals2(int operand1, int operand2, int expected)
{
    //Arrange
    var sut = new Calculator(); //sut-system under test
    //Act
    var result = sut.Add(operand1, operand2);
    //Assert
    Assert.Equal(expected, result);
}

3. 使用外部数据

先创建一个类，准备数据,这里是读取的csv文件的数据

using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace DemoTest.Data
{
    /// <summary>
    /// 读取文件并返回数据集合
    /// </summary>
    public class CalculatorCsvData
    {
        public static IEnumerable<object[]> TestData
        {
            get
            {
	            //把csv文件中的数据读出来，转换
                string[] csvLines = File.ReadAllLines("Data\TestData.csv");
                var testCases = new List<object[]>();
                foreach (var csvLine in csvLines)
                {
                    IEnumerable<int> values = csvLine.Trim().Split(',').Select(int.Parse);
                    object[] testCase = values.Cast<object>().ToArray();
                    testCases.Add(testCase);
                }
                return testCases;
            }
        }
    }
}

2.csv数据

Copy
1,2,3
1,3,4
2,4,6
0,1,1

/// <summary>
/// 数据共享-MemberData-外部数据
/// </summary>
/// <param name="operand1"></param>
/// <param name="operand2"></param>
/// <param name="expected"></param>
[Theory]
[MemberData(nameof(CalculatorCsvData.TestData), MemberType = typeof(CalculatorCsvData))]
public void ShouldAddEquals3(int operand1, int operand2, int expected)
{
    //Arrange
    var sut = new Calculator(); //sut-system under test
    //Act
    var result = sut.Add(operand1, operand2);
    //Assert
    Assert.Equal(expected, result);
}

4. 使用自定义特性，继承自DataAttribute#

   自定义特性

using System.Collections.Generic;
using System.Reflection;
using Xunit.Sdk;

namespace DemoTest.Data
{
    public class CalculatorDataAttribute : DataAttribute
    {
        public override IEnumerable<object[]> GetData(MethodInfo testMethod)
        {
            yield return new object[] { 0, 100, 100 };
            yield return new object[] { 1, 99, 100 };
            yield return new object[] { 2, 98, 100 };
            yield return new object[] { 3, 97, 100 };
        }
    }
}

/// <summary>
/// 数据共享-自定义特性继承自DataAttribute
/// </summary>
/// <param name="operand1"></param>
/// <param name="operand2"></param>
/// <param name="expected"></param>
[Theory]
[CalculatorDataAttribute]
public void ShouldAddEquals4(int operand1, int operand2, int expected)
{
    //Arrange
    var sut = new Calculator(); //sut-system under test
    //Act
    var result = sut.Add(operand1, operand2);
    //Assert
    Assert.Equal(expected, result);
}