Apex訪問說明符和測試類

我在SalesForce Apex代碼中看到一些行爲，我不明白。它似乎破壞了代碼安全規則。我有一個控制器，它看起來是這樣的：Apex訪問說明符和測試類

public with sharing class CaseController { 

    //Properties 
    public Case TheCase { get; private set; } 

    // 
    //Constructor 
    public CaseController(ApexPages.StandardController controller) { 
     //Some unimportant stuff 
    } 

    // 
    //Validates all data coming in from the view and saves the case 
    public PageReference Save() { 
     //Some other unimportant stuff 
    } 
}

和測試，看起來是這樣的：

private static testMethod void Save_WithCompleteCase_SavesCase() 
{ 
    //Given 
    User user = GetTestUser('Standard User'); 
    Product2 theProduct = GetTestProduct(); 
    Case theCase = GetTestCase(user, theProduct); 

    System.runAs(user) { 

     //When 
     CaseController controller = new CaseController(new ApexPages.StandardController(theCase)); 
     controller.TheCase.Subject = 'Test Case'; //Making a change to test it saved 
     PageReference page = controller.Save(); 

     //Then 

    } 
}

請注意，我的控制器有「TheCase」私人二傳手，但我能在測試課上改變它的價值。此代碼可以工作並由SalesForce處理。爲什麼？對於允許他們訪問其他類的私有成員的測試類，有什麼特別的嗎？

謝謝！

來源

2011-03-16 Todd Gardner