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