Using Eclipse for the first time:

1. start Eclipse from the Applications folder
2. accept the default workspace location. Eclipse will store all of the code that you write and any other configuration information for your Java projects in this workspace folder.
3. close the Welcome tab

Creating a new project and class:

1. use File->New to create a new Java Project. Call your new project SocialSecurityTaxCalculator, then click Finish.
2. right-click on your new project name (SocialSecurityTaxCalculator) in the Package Explorer tab, and select New->Class.
3. in the Name: textbox, enter the name of your class as TaxCalculator, and then click Finish. Your new class should now appear in the Eclipse editor.

Implementing the TaxCalculator class:

Implement the following methods in the TaxCalculator class, declaring fields as needed. Use the exact method names specified, with the same return types and parameters. Include a brief javadoc comment explaining the purpose of each method. You do not need to use @param and @return tags in your javadoc comments.

When complete, this class will calculate the social security tax paid by a particular tax payer, depending on that person's salary and whether or not they are self employed.

• a constructor that takes two parameters: the taxpayer's salary in dollars (as an int), and a boolean indicating whether or not the tax payer is self employed (true means self employed).
• an accessor method called getSalary that returns the tax payer's salary as an int
• an accessor method called isSelfEmployed that returns boolean - true if the tax payer is self employed, and false otherwise
• a getTaxBill method that returns double - the total social security tax owed by this tax payer. The tax is calculated as follows:
  • a self employed tax payer pays 15% of all salary up to $84,000, plus 2% of all salary over $84,000
  • a tax paper who is not self employed pays 8% of all salary up to $84,000, plus 2% of all salary over $84,000

Adding a main method:

• add a main method to your TaxCalculator class. Recall that the signature of a main method is:

  public static void main(String [] args) {
  
  }
  

• add code to your main method that creates a TaxCalculator object and then uses System.out.println to print the result of calling each of the other methods. For example:

  public static void main(String [] args) {
      TaxCalculator calc = new TaxCalculator(90000, true);
      System.out.println(calc.getSalary());
      System.out.println(calc.isSelfEmployed());
      System.out.println(calc.getTaxBill());
  }
  

• Run your program by right-clicking on the TaxCalculator class in the Project Explorer tab, and then selecting Run As->Java Application. The results of running your main method should appear in the Console tab at the bottom of the screen. For example, if you used the main method above, the Console should display:

  90000
  true
  12720.0
  

Unit Testing in Eclipse with JUnit 4:

• to create a test class, right-click on TaxCalculator.java (in the Project Explorer tab), then select New->JUnit Test Case. (If JUnit Test Case does not appear in the pop-up menu, select Other, and then JUnit Test Case). Make sure that the radio button for New JUnit 4 test is selected, and then click the link that says "Click here to add JUnit 4 to the build bath" at the bottom of the window. Click OK to close the Build Path window, and then Finish to close the JUnit Test Case window. The file TaxCalculatorTest.java will appear in the Eclipse editor. Note that we are using JUnit 4, which has a slightly different syntax from the JUnit 3 tests you used in COMP 131.
• at the very beginning of TaxCalculatorTest.java, add the line:

  import org.junit.*;
  

  (if it is not already there)
• add a test method for the constructor of the TaxCalculator class. In JUnit 4, test methods are indicated with the @Test annotation. For example, your test method might look like:

  @Test 
  public void testConstructor() {
      // test code goes here
  }
  

• to test the constructor, create a new instance of the TaxCalculator class, call the accessor methods, and check that the values returned are as expected using the methods of class org.junit.Assert as explained in the next bullet.
• useful methods of class org.junit.Assert:
  • Assert.assertEquals(int x, int y) - passes if x and y are the same number, and fails otherwise
  • Assert.assertTrue(boolean b) - passes if b is true, and fails otherwise
  • Assert.assertFalse(boolean b) - passes if b is false, and fails otherwise
  • Assert.assertEquals(double x, double y, double delta) - passes if x and y are different by no more than delta, and fails otherwise

  For example, if the object calc is created as:

  TaxCalculator calc = new TaxCalculator(90000, true);
  

  then all of the following should pass:

  Assert.assertEquals(calc.getSalary(), 9000);
  Assert.assertTrue(calc.isSelfEmployed());
  Assert.assertEquals(calc.getTaxBill(), 12720.0, 0.01);
  

  and all of the following should fail:

  Assert.assertEquals(calc.getSalary(), 9001);
  Assert.assertFalse(calc.isSelfEmployed());
  Assert.assertEquals(calc.getTaxBill(), 12719.0, 0.01);
  

• once you have completed the test method for the constructor, save the TaxCalculatorTest file, and then run your test by right-clicking on TaxCalculatorTest.java in the Project Explorer tab and selecting Run As->JUnit Test. A JUnit tab should appear in the same pane as the Package Explorer, with a green bar if your test passed, and a red bar and error message if your test failed.
• if your test failed, correct your code or test case as needed.
• add additional test methods as needed to achieve statement coverage for the getTaxBill method. Review the testing rules if you do not remember how to do this.
• run your tests

Handing in this Assignment