Mockito

Mockito是一个Java平台的开源，在MIT许可证下发布。该框架允许在自动化单元测试中创建对象（模拟对象），用于测试驱动开发（TDD）或行为驱动开发（BDD）。
该框架的名称和图标是对莫吉托（Mojito，一种饮料）的模仿。
特点.
Mockito允许开发人员验证被测系统（SUT）的行为，而无需事先建立期望。对于模拟对象，有人批评其测试代码与被测系统的紧耦合。Mockito试图通过取消期望规范，来摆脱“期望-运行-验证”的模式。Mockito还提供了一些用于减少的注解。
起源.
Mockito是从扩展的语法和功能开始的。
例子.
下面是一个非耦合的Hello world程序；我们可以对它的某些部分进行单元测试，对其它部分使用模拟对象。
package org.examples;
import java.io.IOException;
public class HelloApplication {
 public static interface Greeter {
 String getGreeting(String subject);
 String getIntroduction(String actor);
 
 public static class HelloGreeter implements Greeter {
 private String hello;
 private String segmenter;
 public HelloGreeter(String hello, String segmenter) {
 this.hello = hello;
 this.segmenter = segmenter;
 public String getGreeting(String subject) {
 return hello + " " + subject; 
 public String getIntroduction(String actor) {
 return actor+segmenter;
 public static interface HelloActable {
 void sayHello(String actor, String subject) throws IOException;
 
 public static class HelloAction implements HelloActable {
 private Greeter helloGreeter;
 private Appendable helloWriter;
 public HelloAction(Greeter helloGreeter, Appendable helloWriter) {
 super();
 this.helloGreeter = helloGreeter;
 this.helloWriter = helloWriter;
 public void sayHello(String actor, String subject) throws IOException { 
 helloWriter.append(helloGreeter.getIntroduction(actor)).append(helloGreeter.getGreeting(subject));
 public static void main(String... args) throws IOException {
 new HelloAction(new HelloGreeter("hello", ": "), System.out).sayHello("application", "world");
启动HelloApplication后，结果如下：
HelloActable组件的单元测试可能如下：
package org.examples;
import static org.mockito.Matchers.any;
import static org.mockito.Matchers.eq;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;
import org.junit.Before;
import org.junit.Test;
import org.examples.HelloApplication.HelloActable;
import org.examples.HelloApplication.HelloAction;
import org.examples.HelloApplication.Greeter;
public class HelloActionUnitTest {
 Greeter helloGreeterMock;
 Appendable helloWriterMock;
 HelloActable helloAction;
 @Before
 public void setUp() {
 helloGreeterMock = mock(Greeter.class);
 helloWriterMock = mock(Appendable.class);
 helloAction = new HelloAction(helloGreeterMock, helloWriterMock);
 
 @Test
 public void testSayHello() throws Exception {
 when(helloWriterMock.append(any(String.class))).thenReturn(helloWriterMock);
 when(helloGreeterMock.getIntroduction(eq("unitTest"))).thenReturn("unitTest : ");
 when(helloGreeterMock.getGreeting(eq("world"))).thenReturn("hi world");
 helloAction.sayHello("unitTest", "world");
 verify(helloGreeterMock).getIntroduction(eq("unitTest"));
 verify(helloGreeterMock).getGreeting(eq("world"));
 verify(helloWriterMock, times(2)).append(any(String.class));
 verify(helloWriterMock, times(1)).append(eq("unitTest : "));
 verify(helloWriterMock, times(1)).append(eq("hi world"));
它为Greeter和Appendable接口使用了模拟对象，并隐式假设了下一个用例：
用于测试Greeter与HelloActable联合在一起的集成测试代码可能如下：
package org.examples;
import static org.mockito.Matchers.any;
import static org.mockito.Matchers.eq;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;
import org.junit.Before;
import org.junit.Test;
import org.examples.HelloApplication.HelloActable;
import org.examples.HelloApplication.HelloAction;
import org.examples.HelloApplication.Greeter;
import org.examples.HelloApplication.HelloGreeter;
public class HelloActionIntegrationTest {
 HelloActable helloAction;
 Greeter helloGreeter;
 Appendable helloWriterMock;
 @Before
 public void setUp() {
 helloGreeter = new HelloGreeter("welcome", " says ");
 helloWriterMock = mock(Appendable.class);
 helloAction = new HelloAction(helloGreeter, helloWriterMock);
 
 @Test
 public void testSayHello() throws Exception {
 when(helloWriterMock.append(any(String.class))).thenReturn(helloWriterMock);
 helloAction.sayHello("integrationTest", "universe");
 verify(helloWriterMock, times(2)).append(any(String.class));
 verify(helloWriterMock, times(1)).append(eq("integrationTest says "));
 verify(helloWriterMock, times(1)).append(eq("welcome universe"));
它仅使用模拟对象代替Appendable接口，而使用其它（HelloActable和Greeter）接口的真实实现，并隐式假设了下一个用例：
从HelloActionUnitTest和HelloActionIntegrationTest这两个类的import语句可以看出，需要在中加入一些Mockito和JUnit的包才能编译和运行测试类。