Scala和使用的Mockito性狀

Question

我做了一個簡單的類，自然地分成兩個部分，所以我重構爲

class Refactored extends PartOne with PartTwo 

然後單元測試啓動失敗。

下面是重新創建問題的嘗試。所有三個示例的功能都是相同的，但第三個測試會失敗，並顯示NullPointerException。什麼是使用導致mockito問題的特質？

編輯： Mockito是Scala的最佳選擇嗎？我使用了錯誤的工具嗎？

import org.scalatest.junit.JUnitSuite 
import org.scalatest.mock.MockitoSugar 
import org.mockito.Mockito.when 
import org.junit.Test 
import org.junit.Before 

class A(val b:B) 
class B(val c:Int) 

class First(){ 
    def getSomething(a:A) = a.b.c 
} 

class Second_A extends Second_B 
class Second_B{ 
    def getSomething(a:A) = a.b.c 
} 

class Third_A extends Third_B 
trait Third_B{ 
    // Will get a NullPointerException here 
    // since a.b will be null 
    def getSomething(a:A) = a.b.c 
} 

class Mocking extends JUnitSuite with MockitoSugar{ 
    var mockA:A = _ 
    @Before def setup { mockA = mock[A] } 

    @Test def first_PASSES { 
     val mockFirst = mock[First] 
     when(mockFirst.getSomething(mockA)).thenReturn(3) 

     assert(3 === mockFirst.getSomething(mockA)) 
    } 

    @Test def second_PASSES { 
     val mockSecond = mock[Second_A] 
     when(mockSecond.getSomething(mockA)).thenReturn(3) 

     assert(3 === mockSecond.getSomething(mockA)) 
    } 

    @Test def third_FAILS { 
     val mockThird = mock[Third_A] 

     //NullPointerException inside here (see above in Third_B) 
     when(mockThird.getSomething(mockA)).thenReturn(3) 

     assert(3 === mockThird.getSomething(mockA)) 
    } 
} 

Answer 1

似乎Mockito在看到階級和特質之間的關係時存在某種問題。猜猜這並不奇怪，因爲特徵在Java中不是原生的。如果你直接嘲笑這個特質本身，它可以工作，但這可能不是你想要做的事情？有幾個不同的特點，你將需要一個模擬每個：

@Test def third_PASSES { 
    val mockThird = mock[Third_B] 

    when(mockThird.getSomething(mockA)).thenReturn(3) 

    assert(3 === mockThird.getSomething(mockA)) 
}