powermockito：如何在枚举中模拟抽象方法 [英] powermockito: How to mock abstract method in enum

问题描述

考虑以下（简化）枚举：

Consider the following (simplified) enumeration:

MyEnum {
    ONE public int myMethod() {
        // Some complex stuff
        return 1;
    },

    TWO public int myMethod() {
        // Some complex stuff
        return 2;
    };

    public abstract int myMethod();
}

这用于以下函数：

void consumer() {
    for (MyEnum n : MyEnum.values()) {
       n.myMethod();
    }
}

我现在想写一个单元测试 consumer ，它在每个枚举实例中模拟对myMethod（）的调用。我尝试了以下内容：

I'd now like to write a unit test for consumer that mocks out the calls to myMethod() in each of the enumeration instances. I've tried the following:

@RunWith(PowerMockRunner.class)
@PrepareForTest(MyEnum.class)
public class MyTestClass {
    @Test
    public void test() throws Exception {
        mockStatic(MyEnum.class);

        when(MyEnum.ONE.myMethod()).thenReturn(10);
        when(MyEnum.TWO.myMethod()).thenReturn(20);

        // Now call consumer()
}

但是正在调用 ONE.myMethod（）和 TWO.myMethod（）的实际实现。

But the real implementations of ONE.myMethod() and TWO.myMethod() are being called.

我做错了什么？

推荐答案

1. 每个常数在枚举中它是一个静态的最终嵌套类。所以要模拟它，你必须在PrepareForTest中使用嵌套类。


2. MyEnum.values（）返回预先初始化的数组，所以它在你的情况下也应该嘲笑。


3. 每个枚举常量只是 public final static 字段。

1. Each constant in enum it's a static final nested class. So to mock it you have to pointe nested class in PrepareForTest.
2. MyEnum.values() returns pre-initialised array, so it should be also mock in your case.
3. Each Enum constant it is just public final static field.

所有在一起：

@RunWith(PowerMockRunner.class)
@PrepareForTest(
value = MyEnum.class,
fullyQualifiedNames = {
                          "com.stackoverflow.q45414070.MyEnum$1",
                          "com.stackoverflow.q45414070.MyEnum$2"
})

public class MyTestClass {

  @Test
  public void should_return_sum_of_stubs() throws Exception {

    final MyEnum one = mock(MyEnum.ONE.getClass());
    final MyEnum two = mock(MyEnum.TWO.getClass());

    mockStatic(MyEnum.class);
    when(MyEnum.values()).thenReturn(new MyEnum[]{one, two});

    when(one.myMethod()).thenReturn(10);
    when(two.myMethod()).thenReturn(20);

    assertThat(new Consumer().consumer())
        .isEqualTo(30);
  }

  @Test
  public void should_return_stubs() {

    final MyEnum one = mock(MyEnum.ONE.getClass());

    when(one.myMethod()).thenReturn(10);

    Whitebox.setInternalState(MyEnum.class, "ONE", one);

    assertThat(MyEnum.ONE.myMethod()).isEqualTo(10);
  }

}

完整示例

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