想使用PowerMock，看这里——PowerMock基本使用

PowerMock，看这里——PowerMock基本使用"/>

想使用PowerMock，看这里——PowerMock基本使用

首先引入依赖：

<dependencies><dependency><groupId>org.powermock</groupId><artifactId>powermock-module-junit4</artifactId><version>2.0.7</version><scope>test</scope></dependency><dependency><groupId>org.powermock</groupId><artifactId>powermock-api-mockito2</artifactId><version>2.0.7</version><scope>test</scope></dependency><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.13</version><scope>test</scope></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.12</version><scope>provided</scope></dependency></dependencies>

Mock普通公共的方法

User

@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
public class User {private Long id;private String name;private Integer age;}

UserDao：

public class UserDAO {// 这里模拟连不上数据库的情况public User getUserById(){throw new UnsupportedOperationException();}}

UserService：

public class UserService {private UserDAO userDAO = new UserDAO();public User getById(){return userDAO.getUserById();}}

测试类：

// 告诉JUnit使用PowerMockRunner进行测试
@RunWith(PowerMockRunner.class)
public class UserServiceTest extends TestCase {@Mockprivate UserDAO userDAO;@InjectMocksprivate UserService userService;@Testpublic void testGetById() {Long id = 1L;Integer age = 11;String name = "花花";Mockito.when(userDAO.getUserById()).thenReturn(User.builder().id(id).age(age).name(name).build());User user = userService.getById();Assert.assertEquals(id,user.getId());}
}

Mock静态方法

静态方法FileUtil

public class FileUtil {public static Boolean fileExists(String path){return true;}
}

FileService:

public class FileService {public Boolean fileExists(String path){return FileUtil.fileExists(path);}
}

测试类：

@RunWith(PowerMockRunner.class)
@PrepareForTest({FileUtil.class})// 因为要mock这个类的静态方法，所以要准备一下
public class FileServiceTest extends TestCase {@InjectMocksprivate FileService fileService;@Beforepublic void init(){PowerMockito.mockStatic(FileUtil.class);// 先声明一下要模拟静态方法}public void testFileExists() {PowerMockito.when(FileUtil.fileExists(Mockito.anyString())).thenReturn(false);Boolean fileExists = fileService.fileExists("C:/user/readme.txt");Assert.assertFalse(fileExists);PowerMockito.when(FileUtil.fileExists(Mockito.anyString())).thenReturn(true);Boolean fileExists1 = fileService.fileExists("C:/user/readme.txt");Assert.assertTrue(fileExists1);}
}

Mock私有方法

StringUtils:

public class StringUtils {public String getString(String source, String subString){if (exsitSubString(source, subString)){return source;} else {return subString;}}private boolean exsitSubString(String source, String subString){return source.contains(subString);}
}

测试类：

@RunWith(PowerMockRunner.class)
@PrepareForTest({StringUtils.class})
public class StringUtilsTest extends TestCase {@InjectMocksprivate StringUtils stringUtils;// mock 私有方法@Testpublic void testGetString() throws Exception {String source = "wangqinjie";String subString = "qin";StringUtils spy = PowerMockito.spy(stringUtils);// 监视某一个对象// mock监视对象调用exsitSubString的方法是返回truePowerMockito.when(spy, "exsitSubString", Mockito.anyString(),Mockito.anyString()).thenReturn(true);String string = spy.getString(source, subString);Assert.assertEquals(source, string);}
}

测试私有方法

有的时候我们为了代码很好的覆盖，我们需要覆盖有些类的私有的方法，那我们可以直接测试类中的私有方法。

注意：是测试私有方法，不是mock

public class DateUtils {private Boolean isAfter30Days(Date startDate, Date endDate){return true;}
}

测试类：

public class DateUtilsTest extends TestCase {// 方式一@Testpublic void testPrivate1() throws InvocationTargetException, IllegalAccessException {// 创建一个对象DateUtils dateUtils = new DateUtils();// 获取这个类的某一个私有的方法。Method method = PowerMockito.method(DateUtils.class, "isAfter30Days", Date.class, Date.class);// 使用对象并传入参数，调用这个私有方法Boolean isAfter = (Boolean) method.invoke(dateUtils, new Date(), new Date());Assert.assertTrue(isAfter);}// 方式二@Testpublic void testPrivate2() throws Exception {// 创建一个对象DateUtils dateUtils = new DateUtils();// 使用Whitebox写盒子直接调用这个对象的私有方法Boolean isAfter = Whitebox.invokeMethod(dateUtils, "isAfter30Days", new Date(), new Date());Assert.assertTrue(isAfter);}}

Mock局部变量

ToolItem

public class ToolItem {public void run(){System.out.println("run");}
}

Tool

public class Tool {public void run() {ToolItem toolItem = new ToolItem();toolItem.run();}
}

ToolService

public class ToolService {public void useTool(Tool tool){tool.run();}
}

测试类：

@RunWith(PowerMockRunner.class)
public class ToolServiceTest extends TestCase {@InjectMocksprivate ToolService toolService;@Mockprivate Tool tool;public void testUseTool() throws Exception {ToolItem toolItem = new ToolItem();PowerMockito.whenNew(ToolItem.class).withNoArguments().thenReturn(toolItem);toolService.useTool(tool);// 证实tool的run方法被调用了，一般是用于证实void方法的Mockito.verify(tool).run();}
}

Mock final方法(类)

Room

final public class Room {public String beSited(){return "be sit";}
}

RoomService

public class RoomService {private Room room;RoomService(Room room){this.room = room;}public String beSit(){return room.beSited();}
}

测试类：

@RunWith(PowerMockRunner.class)
@PrepareForTest({Room.class})
public class RoomServiceTest extends TestCase {@Testpublic void testBeSit() {String sit = "be Sit";Room mock = PowerMockito.mock(Room.class);PowerMockito.when(mock.beSited()).thenReturn(sit);RoomService roomService = new RoomService(mock);String s = roomService.beSit();Assert.assertEquals(sit, s);}
}

另外一种方式：

@RunWith(PowerMockRunner.class)
@PrepareForTest({Room.class})
public class RoomServiceTest extends TestCase {@MockRoom room;@Testpublic void testBeSit() {String sit = "be Sit";PowerMockito.when(room.beSited()).thenReturn(sit);RoomService roomService = new RoomService(room);String s = roomService.beSit();Assert.assertEquals(sit, s);}
}