使用xUnit为.net core程序进行单元测试(3)测试的分组忽略Test打印自定义测试输出信息:减少重复的代码在执行测试的时候共享上下文在不同的测试类中共享上下文

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我是靠谱客的博主跳跃玉米，最近开发中收集的这篇文章主要介绍使用xUnit为.net core程序进行单元测试(3)测试的分组忽略Test打印自定义测试输出信息:减少重复的代码在执行测试的时候共享上下文在不同的测试类中共享上下文，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

第1部分: http://www.cnblogs.com/cgzl/p/8283610.html

第2部分: http://www.cnblogs.com/cgzl/p/8287588.html

请使用这个项目作为练习的开始: https://pan.baidu.com/s/1ggcGkGb

测试的分组

打开Game.Tests里面的BossEnemyShould.cs, 为HaveCorrectPower方法添加一个Trait属性标签:

        [Fact]
        [Trait("Category", "Enemy")]
        public void HaveCorrectPower()
        {
            BossEnemy sut = new BossEnemy();

            Assert.Equal(166.667, sut.SpecialAttackPower, 3);
        }

Trait接受两个参数, 作为测试分类的Name和Value对.

Build项目, Run All Tests, 然后选择选择一下按Traits分组:

这时, Test Explorer里面的tests将会这样显示:

再打开EnemyFactoryShould.cs, 为CreateNormalEnemyByDefault方法添加Trait属性标签:

        [Fact]
        [Trait("Category", "Enemy")]
        public void CreateNormalEnemyByDefault()
        {
            EnemyFactory sut = new EnemyFactory();

            Enemy enemy = sut.Create("Zombie");

            Assert.IsType<NormalEnemy>(enemy);
        }

Build, 然后查看Test Explorer:

不同的Category:

修改一下BossEnemyShould.cs里面的HaveCorrectPower方法的Trait属性:

        [Fact]
        [Trait("Category", "Boss")]
        public void HaveCorrectPower()
        {
            BossEnemy sut = new BossEnemy();

            Assert.Equal(166.667, sut.SpecialAttackPower, 3);
        }

Build之后, 将会看见两个分类:

在Class级别进行分类:

只需要把Trait属性标签移到Class上面即可:

    [Trait("Category", "Enemy")]
    public class EnemyFactoryShould
    {

Build, 查看Test Explorer可以发现EnemyFactoryShould下面所有的Test方法都分类到了Enemy下:

按分类运行测试:

鼠标右键点击分类, Run Selected Tests就会运行该分类下所有的测试:

按Trait搜索:

在Test Explorer中把分类选择到Class:

然后在旁边的Search输入框中输入关键字, 这时下方会有提示菜单:

点击Trait, 然后如下图输入, 就会把Enemy分类的测试过滤显示出来:

这种方式同样也可以进行Trait过滤.

使用命令行进行分类测试

使用命令行进入的Game.Tests, 首先执行命令dotnet test, 这里显示一共有27个tests:

然后, 可以使用命令:

dotnet test --filter Category=Enemy

运行分类为Enemy的tests, 结果如图, 有8个tests:

运行多个分类的tests:

dotnet test --filter "Category=Boss|Category=Enemy"

这句命令会运行分类为Boss或者Enemy的tests, 结果如图:

共有9个tests.

忽略Test

为Fact属性标签设置其Skip属性, 即可忽略该测试, Skip的值为忽略的原因:

        [Fact(Skip = "不需要跑这个测试")]
        public void CreateNormalEnemyByDefault_NotTypeExample()
        {
            EnemyFactory sut = new EnemyFactory();

            Enemy enemy = sut.Create("Zombie");

            Assert.IsNotType<DateTime>(enemy);
        }

Build, 查看Test Explorer, 选择按Trait分类显示, 然后选中Category[Enemy]运行选中的tests:

从这里可以看到, 上面Skip的test被忽略了.

回到命令行, 执行dotnet test:

也可以看到该测试被忽略了, 并且标明了忽略的原因.

打印自定义测试输出信息:

在test中打印信息需要用到ITestOutputHelper的实现类(注意: 这里使用Console.Writeline是无效的), 在BossEnemyShould.cs里面注入这个helper:

using Xunit;
using Xunit.Abstractions;

namespace Game.Tests
{
    public class BossEnemyShould
    {
        private readonly ITestOutputHelper _output;

        public BossEnemyShould(ITestOutputHelper output)
        {
            _output = output;
        }
......

然后在test方法里面这样写即可:

        [Fact]
        [Trait("Category", "Boss")]
        public void HaveCorrectPower()
        {
            _output.WriteLine("正在创建 Boss Enemy");
            BossEnemy sut = new BossEnemy();

            Assert.Equal(166.667, sut.SpecialAttackPower, 3);
        }

Build, Run Tests, 这时查看测试结果会发现一个output链接:

点击这个链接, 就会显示测试的输出信息:

使用命令行:

dotnet test --filter Category=Boss --logger:trx

执行命令后:

可以看到生成了一个TestResults文件夹, 里面是测试的输出文件, 使用编辑器打开, 它是一个xml文件, 内容如下:

<?xml version="1.0" encoding="UTF-8"?>
<TestRun id="9e552b73-0636-46a2-83d9-c19a5892b3ab" name="solen@DELL-RED 2018-02-10 10:27:19" runUser="DELL-REDsolen" xmlns="http://microsoft.com/schemas/VisualStudio/TeamTest/2010">
  <Times creation="2018-02-10T10:27:19.5005784+08:00" queuing="2018-02-10T10:27:19.5005896+08:00" start="2018-02-10T10:27:17.4990291+08:00" finish="2018-02-10T10:27:19.5176327+08:00" />
  <TestSettings name="default" id="610cad4c-1066-417b-a8e6-d30dce78ef4d">
    <Deployment runDeploymentRoot="solen_DELL-RED_2018-02-10_10_27_19" />
  </TestSettings>
  <Results>
    <UnitTestResult executionId="4c6ec739-ccd3-4233-b2bd-8bbde4dfa67f" testId="9e476ed4-3cd9-4f51-aa39-b3d411369979" testName="Game.Tests.BossEnemyShould.HaveCorrectPower" computerName="DELL-RED" duration="00:00:00.0160000" startTime="2018-02-10T10:27:19.2099922+08:00" endTime="2018-02-10T10:27:19.2113656+08:00" testType="13cdc9d9-ddb5-4fa4-a97d-d965ccfc6d4b" outcome="Passed" testListId="8c84fa94-04c1-424b-9868-57a2d4851a1d" relativeResultsDirectory="4c6ec739-ccd3-4233-b2bd-8bbde4dfa67f">
      <Output>
        <StdOut>正在创建 Boss Enemy</StdOut>
      </Output>
    </UnitTestResult>
  </Results>
  <TestDefinitions>
    <UnitTest name="Game.Tests.BossEnemyShould.HaveCorrectPower" storage="c:userssolenprojectsgamegame.testsbindebugnetcoreapp2.0game.tests.dll" id="9e476ed4-3cd9-4f51-aa39-b3d411369979">
      <Execution id="4c6ec739-ccd3-4233-b2bd-8bbde4dfa67f" />
      <TestMethod codeBase="C:UserssolenprojectsGameGame.TestsbinDebugnetcoreapp2.0Game.Tests.dll" executorUriOfAdapter="executor://xunit/VsTestRunner2/netcoreapp" className="Game.Tests.BossEnemyShould" name="Game.Tests.BossEnemyShould.HaveCorrectPower" />
    </UnitTest>
  </TestDefinitions>
  <TestEntries>
    <TestEntry testId="9e476ed4-3cd9-4f51-aa39-b3d411369979" executionId="4c6ec739-ccd3-4233-b2bd-8bbde4dfa67f" testListId="8c84fa94-04c1-424b-9868-57a2d4851a1d" />
  </TestEntries>
  <TestLists>
    <TestList name="Results Not in a List" id="8c84fa94-04c1-424b-9868-57a2d4851a1d" />
    <TestList name="All Loaded Results" id="19431567-8539-422a-85d7-44ee4e166bda" />
  </TestLists>
  <ResultSummary outcome="Completed">
    <Counters total="1" executed="1" passed="1" failed="0" error="0" timeout="0" aborted="0" inconclusive="0" passedButRunAborted="0" notRunnable="0" notExecuted="0" disconnected="0" warning="0" completed="0" inProgress="0" pending="0" />
    <Output>
      <StdOut>[xUnit.net 00:00:00.5525795]   Discovering: Game.Tests[xUnit.net 00:00:00.6567207]   Discovered:  Game.Tests[xUnit.net 00:00:00.6755272]   Starting:    Game.Tests[xUnit.net 00:00:00.8743059]   Finished:    Game.Tests</StdOut>
    </Output>
  </ResultSummary>
</TestRun>

View Code

在里面某个Output标签内可以看到上面写的测试输出信息.

减少重复的代码

xUnit在执行某个测试类的Fact或Theory方法的时候, 都会创建这个类新的实例, 所以有一些公用初始化的代码可以移动到constructor里面.

打开PlayerCharacterShould.cs, 可以看到每个test方法都执行了new PlayerCharacter()这个动作. 我们应该把这段代码移动到constructor里面:

namespace Game.Tests
{
    public class PlayerCharacterShould
    {
        private readonly PlayerCharacter _playerCharacter;
        private readonly ITestOutputHelper _output;

        public PlayerCharacterShould(ITestOutputHelper output)
        {
　　　　　　　_output = output;
            _output.WriteLine("正在创建新的玩家角色");
            _playerCharacter = new PlayerCharacter();
        }

        [Fact]
        public void BeInexperiencedWhenNew()
        {
            Assert.True(_playerCharacter.IsNoob);
        }

        [Fact]
        public void CalculateFullName()
        {
            _playerCharacter.FirstName = "Sarah";
            _playerCharacter.LastName = "Smith";

            Assert.Equal("Sarah Smith", _playerCharacter.FullName);
......

Build, Run Tests, 都OK, 并且都有output输出信息.

除了集中编写初始化代码, 也可以集中编写清理代码:

这需要该测试类实现IDisposable接口:

public class PlayerCharacterShould: IDisposable
    {

......

        public void Dispose()
        {
            _output.WriteLine($"正在清理玩家{_playerCharacter.FullName}");
        }
}

Build, Run Tests, 然后随便查看一个该类的test的output:

可以看到Dispose()被调用了.

在执行测试的时候共享上下文

上面降到了每个测试方法运行的时候都会创建该测试类新的实例, 可以在constructor里面进行公共的初始化动作.

但是如果初始化的动作消耗资源比较大, 并且时间较长, 那么这种方法就不太好了, 所以下面介绍另外一种方法.

首先在Game项目里面添加类:GameState.cs:

using System;
using System.Collections.Generic;

namespace Game
{
    public class GameState
    {
        public static readonly int EarthquakeDamage = 25;
        public List<PlayerCharacter> Players { get; set; } = new List<PlayerCharacter>();
        public Guid Id { get; } = Guid.NewGuid();

        public GameState()
        {
            CreateGameWorld();
        }        

        public void Earthquake()
        {
            foreach (var player in Players)
            {
                player.TakeDamage(EarthquakeDamage);
            }
        }

        public void Reset()
        {
            Players.Clear();
        }

        private void CreateGameWorld()
        {
            // Simulate expensive creation
            System.Threading.Thread.Sleep(2000);
        }
    }
}

View Code

在Game.Tests里面添加类: GameStateShould.cs:

using Xunit;

namespace Game.Tests
{
    public class GameStateShould
    {
        [Fact]
        public void DamageAllPlayersWhenEarthquake()
        {
            var sut = new GameState();

            var player1 = new PlayerCharacter();
            var player2 = new PlayerCharacter();

            sut.Players.Add(player1);
            sut.Players.Add(player2);

            var expectedHealthAfterEarthquake = player1.Health - GameState.EarthquakeDamage;

            sut.Earthquake();

            Assert.Equal(expectedHealthAfterEarthquake, player1.Health);
            Assert.Equal(expectedHealthAfterEarthquake, player2.Health);
        }

        [Fact]
        public void Reset()
        {
            var sut = new GameState();

            var player1 = new PlayerCharacter();
            var player2 = new PlayerCharacter();

            sut.Players.Add(player1);
            sut.Players.Add(player2);

            sut.Reset();

            Assert.Empty(sut.Players);            
        }
    }
}

View Code

看一下上面的代码, 里面有一个Sleep 2秒的动作, 所以执行两个测试方法的话每个方法都会执行这个动作, 一共用了这些时间:

为了解决这个问题, 我们首先建立一个类 GameStateFixture.cs, 它需要实现IDisposable接口:

using System;

namespace Game.Tests
{
    public class GameStateFixture : IDisposable
    {
        public GameState State { get; private set; }

        public GameStateFixture()
        {
            State = new GameState();
        }

        public void Dispose()
        {
            // Cleanup
        }
    }
}

然后在GameStateShould类实现IClassFixture接口并带有泛型的类型:

using Xunit;
using Xunit.Abstractions;

namespace Game.Tests
{
    public class GameStateShould : IClassFixture<GameStateFixture>
    {
        private readonly GameStateFixture _gameStateFixture;
        private readonly ITestOutputHelper _output;

        public GameStateShould(GameStateFixture gameStateFixture, ITestOutputHelper output)
        {
            _gameStateFixture = gameStateFixture;
            _output = output;
        }

        [Fact]
        public void DamageAllPlayersWhenEarthquake()
        {
            _output.WriteLine($"GameState Id={_gameStateFixture.State.Id}");
            
            var player1 = new PlayerCharacter();
            var player2 = new PlayerCharacter();

            _gameStateFixture.State.Players.Add(player1);
            _gameStateFixture.State.Players.Add(player2);

            var expectedHealthAfterEarthquake = player1.Health - GameState.EarthquakeDamage;

            _gameStateFixture.State.Earthquake();

            Assert.Equal(expectedHealthAfterEarthquake, player1.Health);
            Assert.Equal(expectedHealthAfterEarthquake, player2.Health);
        }

        [Fact]
        public void Reset()
        {
            _output.WriteLine($"GameState Id={_gameStateFixture.State.Id}");

            var player1 = new PlayerCharacter();
            var player2 = new PlayerCharacter();

            _gameStateFixture.State.Players.Add(player1);
            _gameStateFixture.State.Players.Add(player2);

            _gameStateFixture.State.Reset();

            Assert.Empty(_gameStateFixture.State.Players);            
        }
    }
}

这个注入的_gameStateFixture在运行多个tests的时候只有一个实例. 所以把消耗资源严重的动作放在GameStateFixture里面就可以保证该段代码只运行一次, 并且被所有的test所共享调用. 要注意的是, 因为上述原因, GameStateFixture里面的代码不可以有任何副作用, 也就是说可以影响其他的测试结果.

Build, Run Tests:

可以看到运行时间少了很多, 因为那段Sleep代码只需要运行一次.

再查看一下这个两个tests的output是一样的, 也就是说明确实是只生成了一个GameState实例:

在不同的测试类中共享上下文

上面讲述了如何在一个测试类中不同的测试里共享代码的方法, 而xUnit也可以让我们在不同的测试类中共享上下文.

在Tests项目里建立 GameStateCollection.cs:

using Xunit;

namespace Game.Tests
{
    [CollectionDefinition("GameState collection")]
    public class GameStateCollection : ICollectionFixture<GameStateFixture> {}
}

这个类GameStateCollection需要实现ICollectionFixture<T>接口, 但是它没有具体的实现.

它上面的CollectionDefinition属性标签作用是定义了一个Collection名字叫做GameStateCollection.

再建立TestClass1.cs:

using Xunit;
using Xunit.Abstractions;

namespace Game.Tests
{
    [Collection("GameState collection")]
    public class TestClass1
    {
        private readonly GameStateFixture _gameStateFixture;
        private readonly ITestOutputHelper _output;

        public TestClass1(GameStateFixture gameStateFixture, ITestOutputHelper output)
        {
            _gameStateFixture = gameStateFixture;

            _output = output;
        }

        [Fact]
        public void Test1()
        {
            _output.WriteLine($"GameState ID={_gameStateFixture.State.Id}");
        }

        [Fact]
        public void Test2()
        {
            _output.WriteLine($"GameState ID={_gameStateFixture.State.Id}");
        }
    }
}

和TestClass2.cs:

using Xunit;
using Xunit.Abstractions;

namespace Game.Tests
{
    [Collection("GameState collection")]
    public class TestClass2
    {
        private readonly GameStateFixture _gameStateFixture;
        private readonly ITestOutputHelper _output;

        public TestClass2(GameStateFixture gameStateFixture, ITestOutputHelper output)
        {
            _gameStateFixture = gameStateFixture;

            _output = output;
        }

        [Fact]
        public void Test3()
        {
            _output.WriteLine($"GameState ID={_gameStateFixture.State.Id}");
        }

        [Fact]
        public void Test4()
        {
            _output.WriteLine($"GameState ID={_gameStateFixture.State.Id}");
        }
    }
}