做单元测试时候，经常会mock一些方法，得到期望的返回值，这里记录一下常见的public、private、static方法，以及设计到的内部调用的方法

一、依赖坐标引入

这里采用maven，引入powermock即可

      <dependency>
          <groupId>org.powermock</groupId>
          <artifactId>powermock-module-junit4</artifactId>
          <version>2.0.9</version>
          <scope>test</scope>
      </dependency>
 
      <dependency>
          <groupId>org.powermock</groupId>
          <artifactId>powermock-api-mockito2</artifactId>
          <version>2.0.9</version>
          <scope>test</scope>
      </dependency>

二、BaseTest基类编写

所有单元测试的测试类都继成BaseTest即可

（1）springboot的示例

import com.abc.WebApplication;
import org.junit.runner.RunWith;
import org.powermock.modules.junit4.PowerMockRunner;
import org.springframework.boot.test.context.SpringBootTest;

@RunWith(PowerMockRunner.class)
@SpringBootTest(classes = WebApplication.class)
public abstract class BaseTest {

}

（2）springmvc的示例

import org.junit.runner.RunWith;
import org.powermock.modules.junit4.PowerMockRunner;
import org.springframework.test.context.ContextConfiguration;

@RunWith(PowerMockRunner.class)
@ContextConfiguration({"classpath:spring.xml","classpath:spring-mvc.xml"})
public class BaseTest {

}

三、单元测试编写

有如下类需要编写单元测试、有三个方法，分别是public、private、static，

mock的类涉及到private和static的，需要在测试类上增加注解@PrepareForTest({私有和静态方法所在的类.class})

（1）需要被单测的类

import javax.annotation.Resource;
import org.springframework.stereotype.Service;

@Service
public class MockTestServiceImpl implements MockTestService {
	@Resource
	private RpcTestGoodPrice rpcTestGoodPrice;

    @Resource
	private TestUtil testUtil;
	
	public String queryRpcPrice(String skuId) {
		String queryRpcPrice = rpcTestGoodPrice.queryRpcPrice(skuId);
		return queryRpcPrice;
	}
	
	public void printRpcPrice(String skuId) {
		String queryRpcPrice = rpcTestGoodPrice.queryRpcPrice(skuId);
		System.out.println(queryRpcPrice);
	}

	private String queryRpcSkuPrice(String skuId) {
		String queryRpcPrice = rpcTestGoodPrice.queryRpcPrice(skuId);
		return queryRpcPrice;
	}

	public String querySkuName(String skuId) {
		String skuName = MockTestServiceImpl.getSkuName(skuId);
		return skuName;
	}
	
	public static String getSkuName(String skuId) {
		return "";
	}

    public void printRpcPrice(String skuId) {
		testUtil.printPrice(skuId);
	}
}

内部涉及到需要调用的其它类 

import org.springframework.stereotype.Service;

@Service
public class RpcTestGoodPrice {

	@Resource
	private GoodPriceProvider goodPriceProvider;
	
	public String queryRpcPrice(String skuId) {
		PriceResult priceResult = goodPriceProvider.queryPrice(skuId);
		return priceResult.getPrice();
	}
}

（2）mock公有方法

import org.junit.Test;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.springframework.test.util.ReflectionTestUtils;

public class MockTestServiceImplTest extends BaseTest {

	@InjectMocks
	private MockTestServiceImpl mockTestServiceImpl;
	
	@InjectMocks
	private RpcTestGoodPrice rpcTestGoodPrice;
	
	@Mock
	private GoodPriceProvider goodPriceProvider;
	
	@Test
	public void testPublic() {
        //预先设置成员变量，可以写在@Before中
		ReflectionTestUtils.setField(mockTestServiceImpl, "rpcTestGoodPrice", rpcTestGoodPrice);
		Mockito.when(goodPriceProvider.queryPrice(Mockito.any())).thenAnswer((m) -> {
			PriceResult result = new PriceResult();
			result.setPrice("22.99");
			return result;
		});
		String skuId = "12345679";
		String queryRpcPrice = mockTestServiceImpl.queryRpcPrice(skuId);
        Assert.assertEquals("22.99", queryRpcPrice);
	}
}

（3）mock私有方法

import org.junit.Test;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.springframework.test.util.ReflectionTestUtils;

@PrepareForTest({MockTestServiceImpl.class})
public class MockTestServiceImplTest extends BaseTest {

	@InjectMocks
	private MockTestServiceImpl mockTestServiceImpl;
	
	@InjectMocks
	private RpcTestGoodPrice rpcTestGoodPrice;
	
	@Mock
	private GoodPriceProvider goodPriceProvider;
	
	@Test
	public void testPrivate() {
		MockTestServiceImpl mockTestServiceImpl = PowerMockito.spy(new MockTestServiceImpl());
        //预先设置成员变量，可以写在@Before中
		ReflectionTestUtils.setField(mockTestServiceImpl, "rpcTestGoodPrice", rpcTestGoodPrice);
		Mockito.when(goodPriceProvider.queryPrice(Mockito.any())).thenAnswer((m) -> {
			PriceResult result = new PriceResult();
			result.setPrice("22.99");
			return result;
		});
		String skuId = "12345679";
		try {
			PowerMockito.when(PowerMockito.spy(new MockTestServiceImpl()),"queryRpcSkuPrice", skuId).thenAnswer((m) -> {
				return "23.99";
			});
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

（4）mock静态方法

import org.junit.Test;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;

@PrepareForTest({MockTestServiceImpl.class})
public class MockTestServiceImplTest extends BaseTest {

	@InjectMocks
	private MockTestServiceImpl mockTestServiceImpl;
	
	@Test
	public void testStatic() {
		PowerMockito.mockStatic(MockTestServiceImpl.class);
		PowerMockito.when(MockTestServiceImpl.getSkuName(Mockito.anyString())).thenAnswer((m) -> {
			return "商品名称";
		});
		String skuId = "12345679";
		String querySkuName = mockTestServiceImpl.querySkuName(skuId);
		Assert.assertEquals("商品名称", querySkuName);
	}
}

（5）mock无返回值的方法

import org.junit.Test;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.powermock.api.mockito.PowerMockito;

public class MockTestServiceImplTest extends BaseTest {

	@InjectMocks
	private MockTestServiceImpl mockTestServiceImpl;
	
	@Mock
	private TestUtil testUtil;
	
	@Test
	public void testVoidPublic() {
        //预先设置成员变量，可以写在@Before中
		Mockito.doNothing().when(testUtil).printPrice(Mockito.any());
		mockTestServiceImpl.printRpcPrice("12345678");
	}
}