之前《有效使用Mock编写java单元测试》一文中层介绍过使用EasyMock和PowerMock来编写java单元测试，今天介绍一个更加强大的工具——JMockit。

1. <</span>dependency>  
2.             <</span>groupId>com.googlecode.jmockit</</span>groupId>  
3.             <</span>artifactId>jmockit</</span>artifactId>  
4.             <</span>version>1.5</</span>version>  
5.             <</span>scope>test</</span>scope>  
6.         </</span>dependency>  
7.         <</span>dependency>  
8.             <</span>groupId>com.googlecode.jmockit</</span>groupId>  
9.             <</span>artifactId>jmockit-coverage</</span>artifactId>  
10.             <</span>version>0.999.24</</span>version>  
11.             <</span>scope>test</</span>scope>  
12.         </</span>dependency>  

1. public class MyObject {  
2.     public String hello(String name){  
3.         return "Hello " + name;  
4.     }  
5. }  

1. @Mocked  //用@Mocked标注的对象，不需要赋值，jmockit自动mock  
2. MyObject obj;  
3.   
4. @Test  
5. public void testHello() {  
6.     new NonStrictExpectations() {//录制预期模拟行为  
7.         {  
8.             obj.hello("Zhangsan");  
9.             returns("Hello Zhangsan");  
10.             //也可以使用：result = "Hello Zhangsan";  
11.         }  
12.     };  
13.     assertEquals("Hello Zhangsan", obj.hello("Zhangsan"));//调用测试方法  
14.     new Verifications() {//验证预期Mock行为被调用  
15.         {  
16.             obj.hello("Hello Zhangsan");  
17.             times = 1;  
18.         }  
19.     };  
20. }  

1. @Test  
2. public void testHello() {  
3.     final MyObject obj = new MyObject();  
4.     new NonStrictExpectations(obj) {//录制预期模拟行为  
5.         {  
6.             obj.hello("Zhangsan");  
7.             returns("Hello Zhangsan");  
8.             //也可以使用：result = "Hello Zhangsan";  
9.         }  
10.     };  
11.     assertEquals("Hello Zhangsan", obj.hello("Zhangsan"));//调用测试方法  
12.     new Verifications() {//验证预期Mock行为被调用  
13.         {  
14.             obj.hello("Hello Zhangsan");  
15.             times = 1;  
16.         }  
17.     };  
18. }  

1. @Test  
2. public void testMockStaticMethod() {  
3.     new NonStrictExpectations(ClassMocked.class) {  
4.         {  
5.             ClassMocked.getDouble(1);//也可以使用参数匹配：ClassMocked.getDouble(anyDouble);  
6.             result = 3;  
7.         }  
8.     };  
9.   
10.     assertEquals(3, ClassMocked.getDouble(1));  
11.   
12.     new Verifications() {  
13.         {  
14.             ClassMocked.getDouble(1);  
15.             times = 1;  
16.         }  
17.     };  
18. }  

1. @Test  
2. public void testMockPrivateMethod() throws Exception {  
3.     final ClassMocked obj = new ClassMocked();  
4.     new NonStrictExpectations(obj) {  
5.         {  
6.             this.invoke(obj, "multiply3", 1);//如果私有方法是静态的，可以使用：this.invoke(null, "multiply3")  
7.             result = 4;  
8.         }  
9.     };  
10.   
11.     String actual = obj.getTripleString(1);  
12.     assertEquals("4", actual);  
13.   
14.     new Verifications() {  
15.         {  
16.             this.invoke(obj, "multiply3", 1);  
17.             times = 1;  
18.         }  
19.     };  
20. }  

public class ClassMocked {
    private String name = "name_init";

    public String getName() {
        return name;
    }
    
    private static String className="Class3Mocked_init";
    
    public static String getClassName(){
        return className;
    }
}

@Test
public void testMockPrivateProperty() throws IOException {
    final ClassMocked obj = new ClassMocked();
    new NonStrictExpectations(obj) {
        {
            this.setField(obj, "name", "name has bean change!");
        }
    };

    assertEquals("name has bean change!", obj.getName());
}

@Test
public void testMockPrivateStaticProperty() throws IOException {
    new NonStrictExpectations(Class3Mocked.class) {
        {
            this.setField(ClassMocked.class, "className", "className has bean change!");
        }
    };

    assertEquals("className has bean change!", ClassMocked.getClassName());
}

public class StateMocked {
    
    public static int getDouble(int i){
        return i*2;
    }
    
    public int getTriple(int i){
        return i*3;
    }
}

@Test
public void testMockNormalMethodContent() throws IOException {
    StateMocked obj = new StateMocked();
    new MockUp() {//使用MockUp修改被测试方法内部逻辑
        @Mock
      public int getTriple(int i) {
                return i * 30;
        }
    };
    assertEquals(30, obj.getTriple(1));
    assertEquals(60, obj.getTriple(2));
    Mockit.tearDownMocks();//注意：在JMockit1.5之后已经没有Mockit这个类，使用MockUp代替，mockUp和tearDown方法在MockUp类中
}

@Test
    public void testGetTriple() {
        new MockUp() {
            @Mock  
            public int getDouble(int i){  
                return i*20;  
            }
        };  
        assertEquals(20, StateMocked.getDouble(1));  
        assertEquals(40, StateMocked.getDouble(2)); 
    }

                                org.apache.maven.plugins
                                maven-surefire-plugin
                                2.12
                                
                                        -javaagent:"${settings.localRepository}"/com/googlecode/jmockit/jmockit-coverage/0.999.24/jmockit-coverage-0.999.24.jar