public void testIllegalCalculate() {
   try {
     interestCalculator.calculate(-10000, 2);
     fail("No exception on illegal argument");
   } catch (IllegalArgumentException e) {
   }
 }
 // main method
 public static void main(String[] args) {
   InterestCalculator application = new InterestCalculator();
   application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 } // end method main
 @Test(expectedExceptions = IllegalArgumentException.class)
 public void illegalCalculate() {
   interestCalculator.calculate(-10000, 2);
 }
 @Test
 public void calculate() {
   double interest = interestCalculator.calculate(10000, 2);
   assertEquals(interest, 1000.0);
 }
 @BeforeMethod
 public void init() {
   interestCalculator = new SimpleInterestCalculator();
   interestCalculator.setRate(0.05);
 }
 protected void setUp() throws Exception {
   interestCalculator = new SimpleInterestCalculator();
   interestCalculator.setRate(0.05);
 }