easy初步学习
话不多说，先上代码，测试一个根据岗位计算工资的类IncomeCalculator

public enum Position {    BOSS, PROGRAMMER, SURFER} public interface ICalcMethod {    double calc(Position position);} public class IncomeCalculator {    private ICalcMethod calcMethod;    private Position position;    public void setCalcMethod(ICalcMethod calcMethod) {        this.calcMethod = calcMethod;    }    public void setPosition(Position position) {        this.position = position;    }    public double calc() {        if (calcMethod == null) {            throw new RuntimeException("CalcMethod not yet maintained");        }        if (position == null) {            throw new RuntimeException("Position not yet maintained");        }        return calcMethod.calc(position);    }} 

public class IncomeCalculatorTest {  private ICalcMethod calcMethod;  private IncomeCalculator calc;  @Before  public void setUp() throws Exception {    // NiceMocks return default values for    // unimplemented methods    calcMethod = createNiceMock(ICalcMethod.class);    calc = new IncomeCalculator();  }  @Test  public void testCalc1() {    // Setting up the expected value of the method call calc    expect(calcMethod.calc(Position.BOSS)).andReturn(70000.0).times(2);    expect(calcMethod.calc(Position.PROGRAMMER)).andReturn(50000.0);    // Setup is finished need to activate the mock    replay(calcMethod);    calc.setCalcMethod(calcMethod);    try {      calc.calc();      fail("Exception did not occur");    } catch (RuntimeException e) {    }    calc.setPosition(Position.BOSS);    assertEquals(70000.0, calc.calc(), 0);    assertEquals(70000.0, calc.calc(), 0);    calc.setPosition(Position.PROGRAMMER);    assertEquals(50000.0, calc.calc(), 0);    calc.setPosition(Position.SURFER);    verify(calcMethod);  }  @Test(expected = RuntimeException.class)  public void testNoCalc() {    calc.setPosition(Position.SURFER);    calc.calc();  }  @Test(expected = RuntimeException.class)  public void testNoPosition() {    expect(calcMethod.calc(Position.BOSS)).andReturn(70000.0);    replay(calcMethod);    calc.setCalcMethod(calcMethod);    calc.calc();  }  @Test(expected = RuntimeException.class)  public void testCalc2() {    // Setting up the expected value of the method call calc    expect(calcMethod.calc(Position.SURFER)).andThrow(new RuntimeException("Don't know this guy")).times(1);    // Setup is finished need to activate the mock    replay(calcMethod);    calc.setPosition(Position.SURFER);    calc.setCalcMethod(calcMethod);    calc.calc();  }} 

软件不是以孤立的方式完成工作，而是大部分单元相互协作完成的。但在单元测试中我们希望忽略协作单元的使用细节，以达到独立完成测试工作的目的。Mock对象能帮助我们在测试环境下代替协作伙伴。而EasyMock为类和接口使用Mock对象提供了一种简单的方式。

对一个类（而非接口）生成mock对象，需要额外jar包Objenesis和Cglib（见附件）；
如果是一个相对复杂的测试用例，需要对多个接口生成mock对象，使用MockControl来管理。

关于easymock更详尽的描述和使用技巧，请参考：
http://www.ibm.com/developerworks/cn/java/j-easymock.html