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}

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.