Purpose

This assignment is aimed at helping you understand how the white box testing method known as control flow testing works. You should have read the slides and section 3.3.2 of the textbook before attempting this assignment.

You are required to complete the tasks described below.

Test software

The following program has been implemented for a newly proposed tax calculation formula for residents of a fictitious country.

// incomeList[]: the array recording the individual income items

// childList[]: the array recording the ages of children supported by this person

// parentList[]: the array recording the ages of parents supported by this person

1. public double computeTax(double[] incomeList, int[] parentList, int[] childList) {
2. double taxAmount = 0.0;
3. double incomeAmount = 0.0;

// calculate the income amount

4. for (int i = 0; i < incomeList.length; i++) {
5. incomeAmount = incomeAmount + incomeList[i]; 6 }

// calculate the basic tax

7. if (incomeAmount <= 40000) {
8. taxAmount = incomeAmount * 0.02;
9. } else if (incomeAmount > 40000 && incomeAmount <= 80000) {
10. taxAmount = 800 + incomeAmount * 0.07;
11. } else if (incomeAmount > 80000 && incomeAmount <= 120000) {
12. taxAmount = 800 + 2800 + incomeAmount * 0.12;
13. } else if (incomeAmount > 120000) {
14. taxAmount = 800 + 2800 + 4800 + incomeAmount * 0.17; 15 }

// calculate the tax exemption from having children

16. int taxExemption = 0;
17. int numOfChild = childList.length;
18. while (numOfChild > 0) {
19. if (childList[numOfChild - 1] < 18) {
20. taxAmount = taxAmount - 4000;
21. taxExemption = taxExemption + 4000; 22 }

23 numOfChild--; 24 }

// calculate the tax exemption from having parents

25. for (int j = 0; j < parentList.length; j++) {
26. if (parentList[j] > 60) {
27. taxAmount = taxAmount - 2000;
28. taxExemption = taxExemption + 2000; 29 }

30 }

// the maximum tax exemption is 8000 each person

31. if (taxExemption <= 8000) {
32. if (taxAmount >= 0) {
33. return taxAmount;
34. } else { // i.e., taxAmount <0
35. return 0; 36 }

37. } else { // i.e., taxExemption > 8000
38. taxAmount = taxAmount + (taxExemption - 8000);
39. return taxAmount; 40 }

41}

Your Tasks

(1) Draw the control flow graph for this program.

(2) Design test cases to achieve the statement coverage on the function computeTax (list the statements covered by each test case using the line number of each statement). If it is not feasible, explain the reason. Use the minimum number of test cases to achieve the statement coverage.

(3) Design test cases to achieve branch coverage on the function computeTax (list the branches covered by each test case). If it is not feasible, explain the reason. Use the minimum number of test cases to achieve the branch coverage.

(4) Design test cases to achieve loop coverage on the function computeTax (list the loops covered by each test case). If it is not feasible, explain the reason. Try your best to use the minimum number of test cases to achieve the loop coverage. Consider a loop covered if at least in one test the loop body was executed 0 times, in a second test the body was executed exactly once, and in another test the body was executed more than once.

Special Instructions

Test cases should be presented in a table with each row showing the following:

Test ID #, input data, statements/branches/loops covered by the test case, expected output and % coverage . You may add additional columns to display key variables such as tax exemption.

See Understanding Software Test Cases for tips on how test cases should be written: http://www.elementool.com/ebook/softwaretestcases.pdf

Code coverage should be shown by listing the statements (using line numbers) for each test case.