單元測試 – 隔離框架Substitute.For

STUB的功能

這邊是NSubstitute的說明：http://nsubstitute.github.io/help/getting-started/
Substitute是.NET裡的一個隔離框架，若要使用，需要額外在測試專案用NUGET去安裝NSubstitute

1. 動態產生假物件
2. 模擬回傳值
3. 測試監聽事件
4. 驗證傳入參數是否正確

使用Subsitute(Sub)
使用方法如下

calculator = Substitute.For<ICalculator>();

1	calculator = Substitute.For<ICalculator>();

設定呼叫某個方法應該回傳的值

calculator.Add(1, 2).Returns(3);
Assert.That(calculator.Add(1, 2), Is.EqualTo(3));

1 2	calculator.Add(1, 2).Returns(3); Assert.That(calculator.Add(1, 2), Is.EqualTo(3));

下面可以驗證是否Add這個FUNC有被呼叫到

calculator.Add(1, 2);
calculator.Received().Add(1, 2);
calculator.DidNotReceive().Add(5, 7);

calculator.Add(1, 2);

calculator.Received().Add(1, 2);

calculator.DidNotReceive().Add(5, 7);

下面的程式能夠判別傳入的參數是不是正確

calculator.Add(10, -5);
calculator.Received().Add(10, Arg.Any<int>());
calculator.Received().Add(10, Arg.Is<int>(x => x < 0));

calculator.Add(10, -5);

calculator.Received().Add(10, Arg.Any<int>());

calculator.Received().Add(10, Arg.Is<int>(x => x < 0));

驗證回傳值是否正確

calculator
   .Add(Arg.Any<int>(), Arg.Any<int>())
   .Returns(x => (int)x[0] + (int)x[1]);
Assert.That(calculator.Add(5, 10), Is.EqualTo(15));

calculator

.Add(Arg.Any<int>(), Arg.Any<int>())

.Returns(x => (int)x[0] + (int)x[1]);

Assert.That(calculator.Add(5, 10), Is.EqualTo(15));

使用Substitute來針對不同狀況實作假介面

這是一個用MOCK方法的範例

using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
//using Microsoft.VisualStudio.TestTools.UnitTesting;
using NUnit.Framework;
using RsaSecureToken;
using Assert = NUnit.Framework.Assert;

namespace RsaSecureToken.Tests
{
    [TestFixture]
    public class AuthenticationServiceTests
    {
        [Test()]
        public void IsValidTest()
        {
            var target = new AuthenticationService(new FakeProfile(), new FakeToken());

            var actual = target.IsValid("joey", "91000000");

            //always failed
            Assert.IsTrue(actual);                       
        }
    }

    public class FakeProfile:IProfile
    {
        
        public string GetPassword(string account)
        {
            if (account == "joey")
            {
                return "91";
            }

            throw new Exception();
        }
    }
    
    public class FakeToken:IRsaToken
    {
        public string GetRandom(string account)
        {
            return "000000";
        }
    }
}

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

//using Microsoft.VisualStudio.TestTools.UnitTesting;

using NUnit.Framework;

using RsaSecureToken;

using Assert = NUnit.Framework.Assert;

namespace RsaSecureToken.Tests

{

[TestFixture]

public class AuthenticationServiceTests

{

[Test()]

public void IsValidTest()

{

var target = new AuthenticationService(new FakeProfile(), new FakeToken());

var actual = target.IsValid("joey", "91000000");

//always failed

Assert.IsTrue(actual);

}

public class FakeProfile:IProfile

{

public string GetPassword(string account)

{

if (account == "joey")

{

return "91";

}

throw new Exception();

}

public class FakeToken:IRsaToken

{

public string GetRandom(string account)

{

return "000000";

}

上面做法有什麼問題？

每一個不同的依賴案例就要製作一個不同的FakeObject，會讓寫測試的時間太久
沒辦法直接從程式碼知道為什麼這樣會是Vaild

動態產生物件的使用完整範例

Subsitute.For<T>()

1	Subsitute.For<T>()

定義假物件行為(stub)

fake.方法(參數).Returns(值)

1	fake.方法(參數).Returns(值)

        [Test()]
        public void IsValidTest()
        {
            var fakeProfile = Substitute.For<IProfile>(); 
            fakeProfile.GetPassword("joey").Returns("91"); 
            
            var fakeToken = Substitute.For<IRsaToken>(); 
            fakeToken.GetRandom("").ReturnsForAnyArgs("000000"); 
            
            var target = new AuthenticationService(fakeProfile, fakeToken);
            var actual = target.IsValid("joey", "91000000");

            //always failed
            Assert.IsTrue(actual);                       
        }
    }

[Test()]

public void IsValidTest()

{

var fakeProfile = Substitute.For<IProfile>();

fakeProfile.GetPassword("joey").Returns("91");

var fakeToken = Substitute.For<IRsaToken>();

fakeToken.GetRandom("").ReturnsForAnyArgs("000000");

var target = new AuthenticationService(fakeProfile, fakeToken);

var actual = target.IsValid("joey", "91000000");

//always failed

Assert.IsTrue(actual);

}

驗證某個函數是否被呼叫

使用mock object assertion
需求：驗證是非法的時候要記一個log

fake.Receive(次數).方法(參數驗證)

1	fake.Receive(次數).方法(參數驗證)

不要用太多mock就算要使用要避免過度指定，也就是當prod code小小變動就導致測試程式壞掉

下面的程式碼可以驗證當呼叫SyncBookOrders()時是不是會呼叫Insert這個函數兩次：

        [Test]
        public void Test_SyncBookOrders_3_Orders_Only_2_book_order()
        {
            var result = new List<Order>
            {
                new Order
                {
                    Type = "Book"
                },
                new Order
                {
                    Type = "Book"
                },
                new Order
                {
                    Type = "Item"
                }
            };
            
            var target = new OrderServiceForTest();
            target.SetOrder(result);
            
            var fakeBookDao = Substitute.For<IBookDao>();
            target.SetDao(fakeBookDao);
            
            target.SyncBookOrders();
            
            fakeBookDao.Received(2).Insert(Arg.Is<Order>(m => m.Type == "Book"));
        }

[Test]

public void Test_SyncBookOrders_3_Orders_Only_2_book_order()

{

var result = new List<Order>

{

new Order

{

Type = "Book"

new Order

{

Type = "Book"

new Order

{

Type = "Item"

}

};

var target = new OrderServiceForTest();

target.SetOrder(result);

var fakeBookDao = Substitute.For<IBookDao>();

target.SetDao(fakeBookDao);

target.SyncBookOrders();

fakeBookDao.Received(2).Insert(Arg.Is<Order>(m => m.Type == "Book"));

}

驗證傳入參數

驗證傳入的參數是否包含某些關鍵字

 _logger.Received(1).Save(Arg.Is<string>(m => m.Contains("joey") && m.Contains("login failed")));

1	_logger.Received(1).Save(Arg.Is<string>(m => m.Contains("joey") && m.Contains("login failed")));

Claire's Blog

單元測試 – 隔離框架Substitute.For

STUB的功能

使用Substitute來針對不同狀況實作假介面

動態產生物件的使用完整範例

驗證某個函數是否被呼叫

驗證傳入參數

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