Powermockito 針對方法中new 對象的模擬，以及屬性中new 對象的模擬

PowerMocker 是一個功能逆天的mock 工具。

一，Powermockito 針對方法中new 對象的模擬

// 如何才能mock掉 WeChatConfigUtil 這個類，讓 weChatConfigUtil.getMainApploginSwitch();這個方法返回你想要的結果
public void testA(){
    WeChatConfigUtil weChatConfigUtil = new WeChatConfigUtil();
    weChatConfigUtil.getMainAppLoginSwitch();
  }

 

針對上述情況

package com.ppdai.wechat.sub.business.msgsub;

import com.ppdai.wechat.sub.util.WeChatConfigUtil;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

/**
 * Created by huxuhong on 2020/7/2.
 */
//重點，要幫要mock的類（此例為weChatConfigUtil 所在的類TestC，要放到PrepareForTest中即可）
@PrepareForTest(
        {   TestB.TestC.class
        })
@RunWith(PowerMockRunner.class)
public class TestB {
    public TestB(){

    }
    class TestC{
        public void testA(){
            WeChatConfigUtil weChatConfigUtil = new WeChatConfigUtil();
            Boolean flag = weChatConfigUtil.getMainAppLoginSwitch();
            System.out.println("mock結果"+flag);
        }
    }

    @Test
    public void testTestC(){
        TestC testC = new TestC();
        WeChatConfigUtil weChatConfigUtil = PowerMockito.mock(WeChatConfigUtil.class);
        try {
            PowerMockito.whenNew(WeChatConfigUtil.class).withAnyArguments().thenReturn(weChatConfigUtil);
            PowerMockito.doReturn(Boolean.TRUE).when(weChatConfigUtil).getMainAppLoginSwitch();
            testC.testA();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

運行結果

 

二，如何解決屬性中new 對象的模擬

 

public class TestB {
    public TestB(){

    }
    class TestC{
       //如何mock掉屬性中new 對象（此例為WechatConfigUtil weChatConfigUtil = new WechatConfigUtil,讓 weChatConfigUtil.getUserInfoApiUrl 能獲取到指定的值）
        WeChatConfigUtil weChatConfigUtil = new WeChatConfigUtil();
        public void testA(){
            String t = weChatConfigUtil.getUserInfoApiUrl();
            System.out.println("mock結果"+t);
        }
    }

　　

針對上述情況

public class TestB {
    public TestB(){

    }
    class TestC{
        //如果熟悉修飾為pubilc final static WechatConfigUtil,那么就需要和上面的例子一樣要配置@PrepareForTest
        WeChatConfigUtil weChatConfigUtil = new WeChatConfigUtil();
        public void testA(){
            String t = weChatConfigUtil.getUserInfoApiUrl();
            System.out.println("mock結果"+t);
        }
    }

    @Test
    public void testTestC(){
        TestC testC = new TestC();
        WeChatConfigUtil weChatConfigUtil = PowerMockito.mock(WeChatConfigUtil.class);
        try {
            Field weChatConfigUtilField =  testC.getClass().getDeclaredField("weChatConfigUtil");
            weChatConfigUtilField.setAccessible(Boolean.TRUE);
            weChatConfigUtilField.set(testC,weChatConfigUtil);
            PowerMockito.doReturn("testpc").when(weChatConfigUtil).getUserInfoApiUrl();
            testC.testA();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }


}

　　運行結果

 

 

 

三，引入Powermock的時候注意和mockito的版本匹配問題

  Powermock 使用過程中遇到的坑

   ①，使用Powermock mock 靜態方法時，提示下面錯誤

        org.mockito.exceptions.misusing.NotAMockException: Argument should be a mock, but is: class java.lang.Class

         處理方式：版本問題，修改為  mockito 2.25.0，powermock 2.0.2，

        issue https://github.com/powermock/powermock/issues/992#ref-commit-3479902

   

mockito 2.25.0和powermock 2.0.2