使用PowerMock,Mockito和TestNG模拟公共方法中使用的私有方法

Question

我想为我上课写一个单元测试.这个类有一个公共方法,在public方法中,在同一个类中调用私有方法.我想模拟对这些私有方法的调用.该类与此类似:

public class SomeClass {
    public int somePublicMethod(int num) {
        int num2 = somePrivateMethod1(num);
        int num3 = somePrivateMethod2(num);

        return num2 + num3;
    }

    private int somePrivateMethod1(int num) {
        return 2*num;
    }

    private int somePrivateMethod2(int num) {
        return 3*num;
    }
}

对于我的单元测试,我试图将PowerMock与Mockito和TestNG一起使用.这是我尝试测试somePublicMethod的测试:

import static org.powermock.api.mockito.PowerMockito.doReturn;
import static org.powermock.api.mockito.PowerMockito.spy;

import org.powermock.core.classloader.annotations.PrepareForTest;
import org.testng.Assert;
import org.testng.annotations.Test;

@PrepareForTest(SomeClass.class)
public class SomeClassTest {

    @Test
    public void testSomePublicMethod() throws Exception {
        int num = 4;        

        SomeClass someClassSpy = spy(new SomeClass());

        doReturn(8).when(someClassSpy, "somePrivateMethod1", num);
        doReturn(12).when(someClassSpy, "somePrivateMethod2", num);

        int result = someClassSpy.somePublicMethod(num);

        Assert.assertEquals(result, 20);
    }
}

当我运行此测试时,我得到一个异常和一些提示:

FAILED: testSomePublicMethod
org.mockito.exceptions.misusing.UnfinishedStubbingException: 
Unfinished stubbing detected here:
-> at org.powermock.api.mockito.internal.PowerMockitoCore.doAnswer(PowerMockitoCore.java:31)

E.g. thenReturn() may be missing.
Examples of correct stubbing:
    when(mock.isOk()).thenReturn(true);
    when(mock.isOk()).thenThrow(exception);
    doThrow(exception).when(mock).someVoidMethod();
Hints:
 1. missing thenReturn()
 2. you are trying to stub a final method, you naughty developer!

我在网上查看了一些例子,但我没有找到一个将Mockito和TestNG专门用于PowerMock来做我想做的事情.有人可以给我一些关于我能做些什么的指示吗？

Answer 1

我不认为这是PowerMock的问题.它看起来应该工作得很好.我想知道TestNG与PowerMock交互是否存在问题？

我没有使用TestNG的经验,所以我尝试在JUnit中运行该类. SomeClass保留原样,SomeClassTest最低限度修改为使用JUnit:

import static org.powermock.api.mockito.PowerMockito.*;

import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

@RunWith(PowerMockRunner.class)
@PrepareForTest(SomeClass.class)
public class SomeClassTest {

    @Test
    public void testSomePublicMethod() throws Exception {
        final int num = 4;

        final SomeClass someClassSpy = spy(new SomeClass());

        doReturn(8).when(someClassSpy, "somePrivateMethod1", num);
        doReturn(12).when(someClassSpy, "somePrivateMethod2", num);

        final int result = someClassSpy.somePublicMethod(num);

        Assert.assertEquals(result, 20);
    }
}

测试通过.

您是否需要指定PowerMockRunner.class使用@RunWIth或类似的注释,如JUnit？如果我删除该注释,我会收到您发布的相同错误消息.

编辑:

根据此链接:http: //code.google.com/p/powermock/wiki/TestNG_usage

您需要告诉TestNG使用PowerMock对象工厂.要以编程方式执行此操作,请将以下方法添加到测试类:

@ObjectFactory
public IObjectFactory getObjectFactory() {
    return new org.powermock.modules.testng.PowerMockObjectFactory();
}

或者为了安全起见,您还可以从PowerMockTestCase扩展:

@PrepareForTest(SomeClass.class)
public class SomeClassTest extends PowerMockTestCase {
   //...
}