嘲笑使用PowerMock链式方法调用

Question

我有一个类，我想用包含一些链式方法调用的公共静态方法来测试。假设在链式方法调用期间发生异常，我如何有效地处理它并使其返回一些特定的值？

以下是测试类的代码示例。

@RunWith(PowerMockRunner.class) 
@PrepareForTest({CodeWithPrivateMethod.class,CodeWithAnotherPrivateMethod.class,CodeWithYetAnotherPrivateMethod.class}) 
public class CodeWithPrivateMethodTest { 

@Test 
public void when_gambling_is_true_then_always_explode() throws Exception { 


    CodeWithYetAnotherPrivateMethod codeWithYetAnotherPrivateMethod = PowerMockito.spy(new CodeWithYetAnotherPrivateMethod()); 
    PowerMockito.whenNew(CodeWithYetAnotherPrivateMethod.class).withAnyArguments().thenReturn(codeWithYetAnotherPrivateMethod); 

    CodeWithAnotherPrivateMethod codeWithAnotherPrivateMethod = PowerMockito.spy(new CodeWithAnotherPrivateMethod()); 
    PowerMockito.whenNew(CodeWithAnotherPrivateMethod.class).withAnyArguments().thenReturn(codeWithAnotherPrivateMethod); 

    PowerMockito.doReturn(true).when(codeWithYetAnotherPrivateMethod, "getGambling"); 

    //PowerMockito.doReturn(codeWithYetAnotherPrivateMethod).when(codeWithAnotherPrivateMethod, "getGambleValue"); 

    PowerMockito.spy(CodeWithPrivateMethod.class); 
    CodeWithPrivateMethod.startGamble(); 

    } 

} 

以下是该类测试

public class CodeWithPrivateMethod { 

public static void startGamble() { 

    Boolean gamble = CodeWithAnotherPrivateMethod.getGambleValue() 
      .getGambling(); 
    if (gamble) { 
     System.out.println("kaboom"); 
    }else{ 
     System.out.println("boom boom"); 
    } 
    } 
} 

下面的代码示例是为类的代码示例，但未通过类下的测试，称为

public class CodeWithAnotherPrivateMethod { 

static CodeWithYetAnotherPrivateMethod codeWithYetAnotherPrivateMethod = new CodeWithYetAnotherPrivateMethod(); 


public static CodeWithYetAnotherPrivateMethod getGambleValue() { 
    return codeWithYetAnotherPrivateMethod; //works fine 
    return null; // fails 
    } 
} 

以下是代码sa mple为其他类，但未通过类测试

public class CodeWithYetAnotherPrivateMethod { 

public Boolean getGambling() { 
    return false; 
    } 
} 

称为所以假设我从getGambleValue CodeWithAnotherPrivateMethod类的（）方法返回一个空值，我怎么在我的TestClass有效地处理这个空值？

Answer 1

这是如何使用指定预期异常的Mockito：

@Test(expected = NullPointerException.class) 
public void when_gambling_is_true_then_always_explode() throws Exception { 
    ... 

之前，我发现了这一点，我会做：

@Test 
public void when_gambling_is_true_then_always_explode() throws Exception { 
    // setup omitted 
    try { 
     CodeWithPrivateMethod.startGamble(); 
    } 
    catch(NullPointerException e) { 
     // expected 
     return; 
    } 
    fail("Expected NullPointerException"); 
} 

编辑：静态地打电话给对方这样的测试多个类是一种严重的代码味道。单元测试应该测试一个类，而内联静态调用应该限于实用类。

另一种评论：您的示例类名非常混乱。下次请用Foo，Bar，Baz或Appple，梨，香蕉。

如果你没有得到一个NPE，那么我希望你的嘲笑/间谍是干扰。如果调用代码测试无嘲讽/间谍调用链将是：

CodeWithPrivateMethod.startGamble(); 
-> 
CodeWithYetAnotherPrivateMethod value = CodeWithAnotherPrivateMethod.getGambleValue(); 
-> 
return null; 
<- 
value.getGambling(); 
<- throws NullPointerException 

究竟是什么你试图找出或达到什么？

编辑：下面是它应该如何与PowerMock

工作

@RunWith(PowerMockRunner.class) 
@PrepareForTest(CodeWithAnotherPrivateMethod.class) 
public class CodeWithPrivateMethodTest { 

    @Mock 
    private CodeWithYetAnotherPrivateMethod yetAnotherInstance; 

    @Test 
    public final void testStartGamble() { 

    // SETUP 
    mockStatic(CodeWithAnotherPrivateMethod.class); 
    expect(CodeWithAnotherPrivateMethod.getGambleValue()) 
     .andReturn(yetAnotherInstance); 
    Boolean gamblingValue = true; 
    expect(yetAnotherInstance.getGambling()).andReturn(gamblingValue); 
    replayAll(); 

    // CALL 
    CodeWithPrivateMethod.startGamble(); 

    // VERIFY 
    verifyAll(); 
    }