鼴鼠System.Random

Question

類

我有以下方法進行測試：

public float coverageJump(bool a) 
{ 
    int c = 0; 
first: 
    c++; 
    Random random = new Random(); 
    float result = random.Next(0, 100); 
    Console.WriteLine(result); 

    if(result < 50) 
     goto first; 
    if (result == 50) 
     goto end; 

    if (a) 
     goto end; 
    else 
     goto first; 

end: 
    return c; 
} 

Pex的建議我使用Random.Next moled及其創造：

PexMethod：

[PexMethod] 
public float coverageJump([PexAssumeUnderTest]ClassMethod target, bool a) 
{ 
    float result = target.coverageJump(a); 
    return result; 
    // TODO: add assertions to method ClassMethodTest.coverageJump(ClassMethod, Boolean) 
} 

參數化單元測試

[TestMethod] 
[PexGeneratedBy(typeof(ClassMethodTest))] 
[PexRaisedException(typeof(NullReferenceException))] 
[HostType("Moles")] 
public void coverageJumpThrowsNullReferenceException489() 
{ 
    float f; 
    RandomPreparation.Prepare(); 
    ClassMethod s0 = new ClassMethod(); 
    f = this.coverageJump(s0, false); 
} 

而準備的方法來嘲笑Random類：

[PexPreparationMethod(typeof(Random))] 
public static void Prepare() 
{ 
    MRandom.BehaveAsCurrent(); 
} 

我公司開發的準備方法來模擬Random類

MRandom.BehaveAsCurrent(); 
MRandom mr = new MRandom() 
{ 
    NextInt32Int32 = (b, c) => { return 1; }, 
    Sample =() => { return 1; }, 
    InternalSample =() => { return 1; } 
}; 

MRandom.Constructor = (a) => 
{ 
    // a.Next = (b, c) => { return 1; }; 
}; 

MRandom.Behavior = mr.InstanceBehavior; 

但我得到以下NULL異常：

--- Description 
failing test: NullReferenceException, Riferimento a un oggetto non impostato su un'istanza di oggetto. 

float f; 
RandomPreparation.Prepare(); 
ClassMethod s0 = new ClassMethod(); 
f = this.coverageJump(s0, false); 


[TestMethod] 
[PexGeneratedBy(typeof(ClassMethodTest))] 
[PexRaisedException(typeof(NullReferenceException))] 
[HostType("Moles")] 
public void coverageJumpThrowsNullReferenceException387() 
{ 
    float f; 
    RandomPreparation.Prepare(); 
    ClassMethod s0 = new ClassMethod(); 
    f = this.coverageJump(s0, false); 
} 

---

異常詳細

System.NullReferenceException: Riferimento a un oggetto non impostato su un'istanza di oggetto.  at System.Int32 System.Random.InternalSample() 
     at System.Double System.Random.Sample() 
     at System.Int32 System.Random.Next(System.Int32 minValue, System.Int32 maxValue) 
    D:\Sviluppo\UNI\TesiTirocinio\src\TutorialsMolePex\BenchMarkTesterTool\BenchMarkTesterToolLib\ClassMethod.cs(154): at System.Single BenchMarkTesterToolLib.ClassMethod.coverageJump(System.Boolean a) 
    D:\Sviluppo\UNI\TesiTirocinio\src\TutorialsMolePex\BenchMarkTesterTool\BenchMarkTesterToolLib.Tests\ClassMethodTest.cs(27): at System.Single BenchMarkTesterToolLib.ClassMethodTest.coverageJump(BenchMarkTesterToolLib.ClassMethod target, System.Boolean a) 

任何人都可以在這方面幫助？

Answer 1

我覺得這是解決我的問題在準備方法：）

準備（：

[PexPreparationMethod(typeof(Random))] 
    public static void Prepare() 
    { 
     MRandom.Behavior = MoleBehaviors.Fallthrough; 
     MRandom.AllInstances.NextInt32Int32 = (r, a, b) => { return 50; }; 
    } 

我想使用另一種實現

 var fake = new SRandom { CallBase = true }; 
     var mole = new MRandom(fake) 
     { 
      NextInt32Int32 = (a, b) => { return 1; } 
     }; 
     MRandom.BehaveAsCurrent(); 

，但不起作用。有一段時間，我認爲我不能嘲笑隨機的方法下一步，因爲在鼴鼠手動參考報告： ..痣框架來創建鼴鼠類型，利用運行時儀器。用靜態方法，密封類型，或非虛方法的API打交道時，他們是有用的..

和隨機的方法，接下來是：

 public virtual int Next(
      int minValue, 
      int maxValue 
     ) 

可能有人給我一個解釋，因爲我的「準備」方法工作？

非常感謝，最好的問候。