单元测试-Junit-Mockit-PowerMock

0. Junit5

1. Junit4

//手动命令行测试
java -cp /usr1/junit:/usr1/cdncms/lib/* org.junit.runner.JUnitCore com.test.DomainServiceTest

<dependency>
  <groupId>junit</groupId>
  <artifactId>junit</artifactId>
  <version>4.12</version>
  <scope>test</scope>
</dependency>

1.0 执行报错java.lang.VerifyError: Expecting a stackmap frame at branch target 122

增加配置项： windsows-->installJREs-->edit -->  VM arguments --> 增加 -noverify

1.1 Junit注解

@BeforeClass 针对所有测试，只执行一次，且必须为static void

@Before： 初始化方法

@Test： 测试方法，在这里可以测试期望异常和超时时间

@After： 释放资源

@AfterClass： 针对所有测试，只执行一次，且必须为static void

@Ignore： 忽略的测试方法

一个单元测试用例执行顺序为： @BeforeClass –> @Before –> @Test –> @After –> @AfterClass

每一个测试方法的调用顺序为： @Before –> @Test –> @After

1.2 Assert类

assertEquals(boolean expected, boolean actual)	检查两个变量或者等式是否平衡
assertFalse(boolean condition)		检查条件是假的
assertNotNull(Object object)	检查对象不是空的
assertNull(Object object)	检查对象是空的
assertTrue(boolean condition)	检查条件为真
fail()	在没有报告的情况下使测试不通过

junit匹配抛出异常

    @Test(expected = IllegalArgumentException.class)
    public void canVote_throws_IllegalArgumentException_for_zero_age() {.......}

2. Mockito--创建 Mock 对象并且定义它的行为

2.1

a). 静态方法： import static org.mockito.Mockito.*;
b). 验证方法是否调用： verify(test, times(2)).getUniqueId();

2.2 示例

基本用法: （无法对static method和private method进行插桩）
                when(cls.methodName(args)).thenReturn(args)	//对指定语句进行插桩
                when(cls.methodName(args)).thenThrow(Exception)	//抛出异常

1、 基本示例
                LinkedList mockedList = mock(LinkedList.class);

                //插桩
                when(mockedList.get(0)).thenReturn("first");
                when(mockedList.get(1)).thenThrow(new RuntimeException());

                System.out.println(mockedList.get(0));	//输出"first"

                System.out.println(mockedList.get(1));	//抛出异常

                System.out.println(mockedList.get(999));	//输出 null , 因为get(999)未插桩

2、 插桩时可用 Matcher.anyString()/anyInt() 等进行入参匹配
                when(mockedList.get(anyInt())).thenReturn("element");

3、 针对void方法抛出异常
                doThrow(new RuntimeException()).when(mockedList).clear();

4、 针对void方法插桩
                doNothing().when(spy).clear();

3. PowerMock--插桩，static/final/private

3.1 原理

//两个重要注解 -- 使用ASM生成代理类进行mock
	 @RunWith(PowerMockRunner.class)	//通用配置
	 @PrepareForTest( { YourClassWithEgStaticMethod.class })	//需要powermock处理的class，static、final、私有方法等功能
 1) 例如：去除'final方法的final标识，在静态方法的最前面加入自己的虚拟实现等。
 2) 如果mock的是系统类的final/static，PowerMock会修改调用系统类的class文件，以满足mock需求。

 	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<powermock.version>1.7.1</powermock.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.powermock</groupId>
			<artifactId>powermock-module-junit4</artifactId>
			<version>${powermock.version}</version>
			<scope>test</scope>
		</dependency>
		<dependency>
			<groupId>org.powermock</groupId>
			<artifactId>powermock-api-mockito</artifactId>
			<version>${powermock.version}</version>
			<scope>test</scope>
		</dependency>
	</dependencies>

//通过PowerMock创建一个虚拟对象
InterfaceToMock mock = Powermockito.mock(InterfaceToMock.class)

//value为你想要让这个method返回的值
Powermockito.when(mock.method(Params…)).thenReturn(valueToReturn)

//如果这个方法返回值为空，则上面的写法会报错,可采用下面的写法
Powermockito.when(mock, “methodName”, Object… params).thenReturn(valueToReturn)

// 也可以采用下面的写法，和上面的一样的效果
Powermockito.doReturn(valueToReturn).when(mock, “methodName”, Object… params)

//这样写也行，适合返回值为void的方法
Powermockito.doReturn(valueToReturn).when(mock).methodName(Object… params)

//你也可以让方法抛异常
Powermockito.when(mock.method(Params..)).thenThrow(new OMSException(“oms”))

//你可以让方法每一次返回的结果都不一样,下面的例子第一次正常返回，第二次调用抛异常
Powermockito.when(mock.method(Params..)).thenReturn(valueToReturn).thenThrow(new OMSException(“some Exception”))

//如果方法返回值为void,不能用thenReturn,要用doThing()
Powermockito.doNothing().when(mock.method(Params…))

3.2 示例1-mock static方法

public class IdGenerator {
  public static long generateNewId() {
    return 0L;
  }
}

public class ClassUnderTest {
    public long methodToTest() {
          final long id = IdGenerator.generateNewId();
          return id;
    }
}

@RunWith(PowerMockRunner.class)
@PrepareForTest(IdGenerator.class)
public class TestStatic {
    @Test
    public void testCallInternalInstance() throws Exception {
          PowerMockito.mockStatic(IdGenerator.class);
          // 在这个测试用例中,当generateNewId()每次被调用时,都会返回15
          PowerMockito.when(IdGenerator.generateNewId()).thenReturn(15L);
          Assert.assertEquals(15L, new ClassUnderTest().methodToTest());
  }
}

3.2 示例2-模拟构造方法

public class ClassUnderTest {
      public boolean createDirectoryStructure(String directoryPath) {
            File directory = new File(directoryPath);
            if (directory.exists()) {
                  String msg = "\"" + directoryPath + "\" 已经存在.";
                  throw new IllegalArgumentException(msg);
            }
            return directory.mkdirs();
      }
}

@RunWith(PowerMockRunner.class)
@PrepareForTest(ClassUnderTest.class)
public class TestConstruction {
    //模拟构造函数
    @Test
    public void createDirectoryStructureWhenPathDoesntExist() throws Exception {
            final String directoryPath = "seemygod";
            //创建File的模拟对象
            File directoryMock = mock(File.class);
            //在当前测试用例下,当出现new File("seemygod")时,就返回模拟对象
            whenNew(File.class).withArguments(directoryPath).thenReturn(directoryMock);
            //当调用模拟对象的exists时,返回false
            when(directoryMock.exists()).thenReturn(false);
            //当调用模拟对象的mkdirs时,返回true
            when(directoryMock.mkdirs()).thenReturn(true);
            assertTrue(new ClassUnderTest().createDirectoryStructure(directoryPath));
            //验证new File(directoryPath);  是否被调用过
            verifyNew(File.class).withArguments(directoryPath);
    }
}

3.4 用例3-模拟私有以及 Final 方法

public class PrivatePartialMockingExample {
    public String methodToTest() {
            return methodToMock("input");
    }
    private String methodToMock(String input) {
            return "REAL VALUE = " + input;
    }
}

import static org.powermock.api.mockito.PowerMockito.*;
@RunWith(PowerMockRunner.class)
@PrepareForTest(PrivatePartialMockingExample.class)
public class PrivatePartialMockingExampleTest {
    @Test
    public void demoPrivateMethodMocking() throws Exception {
            final String expected = "TEST VALUE";
            final String nameOfMethodToMock = "methodToMock";
            final String input = "input";
            PrivatePartialMockingExample underTest = spy(new PrivatePartialMockingExample());
            //模拟私有方法
			when(underTest, nameOfMethodToMock, input).thenReturn(expected);
            assertEquals(expected, underTest.methodToTest());
            verifyPrivate(underTest).invoke(nameOfMethodToMock, input);
    }
}

3.5 用例4-mock系统类的静态和final方法

public class ClassUnderTest {
    public boolean callSystemFinalMethod(String str) {
        return str.isEmpty();
    }
    public String callSystemStaticMethod(String str) {
        return System.getProperty(str);
    }
}

$RunWith(PowerMockRunner.class)
public class TestClassUnderTest {
   $Test
   $PrepareForTest(ClassUnderTest.class)
   public void testCallSystemStaticMethod() {
      ClassUnderTest underTest = new ClassUnderTest();  

      PowerMockito.mockStatic(System.class);  

      PowerMockito.when(System.getProperty("aaa")).thenReturn("bbb");

      Assert.assertEquals("bbb", underTest.callJDKStaticMethod("aaa"));
  }
}

3.6 用例-PowerMock处理注解

//PushMsgPostProcessorImpl 是要测试的类，它有两个注解注入的类变量如下：
	@Resource
	 private IMsgToUserService msgToUserService;
//则测试类中可以使用下面的方法注入
	@Mock
	 private IMsgToUserService msgToUserService;
	 @Before
	 public void setup() {
	  MockitoAnnotations.initMocks(this);
	  pushMsgPostProcessor = new PushMsgPostProcessorImpl();
	  //给注解的private变量塞一个值
	  ReflectionTestUtils.setField(pushMsgPostProcessor, "msgToUserService", msgToUserService);
	 }

3.10 模拟异常

3.10.1 抛出异常-不带参数

//PowerMockito.when(IOUtils.xMLReader()).thenThrow(SAXException.class);
public class IOUtils {
	public static String xMLReader() throws SAXException {
		return "abc";
	}
}

3.10.2 抛出异常-待参数的异常

//PowerMockito.doThrow(new SAXException()).when(IOUtils.class);
public class IOUtils {
	public static String xMLReader(SAXReader reader) throws SAXException {
		System.out.println("IOUtils.xMLReader");
		if (null == reader) {
			throw new SAXException();
		}
		return "abc";
	}
}