Tutorial-13 To Generate Decision Table based Test Cases for a Payroll Problem

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Tutorial-13: To Generate Decision Table based Test Cases for a Payroll Problem

Objective of the Tutorial: To generate test cases for the payroll problem based upon decision table based testing technique

Consider the payroll system of a person

(a) If the salary of a person is less than equal to Rs. 70,000 and expenses do not exceed Rs. 30,000 then 10% tax is charged by IT department.

(b) If the salary is greater than Rs.60,000 and less than equal to Rs 2lakhs and expenses don’t exceed Rs. 40,000 than 20% tax is charged by IT department.

(c) For salary greater than Rs 2 lakhs, 5% additional surcharge is also charged. (d) If expenses are greater than Rs. 40,000 surcharge is 9%.

Step 1: First of all we need to identify the causes and its effects.

Causes

Effects

C1 : Salary < = 70,000

C2 : Salary > 60,000 and Salary < = 2 lacs

C3 : Salary > 2 lacs

C4 : Expenses < = 30,000

C5 : Expenses < = 40,000

C6 : Expenses > 40,000

E1 : 10% tax is charged.

E2 : 20% tax is charged.

E3 : (20% tax) + (5% surcharge) is charged.

E4 : (20% tax) + (9% surcharge) is charged.

Step 2: Draw the following cause-effect graph

Cause-Effect Graph

Step 3: Transform cause-effect graph into the following decision table. It may be noted that these ’causes’ and ‘effects’ are nothing else but ‘conditions’ and ‘actions’ of our decision table.

		1	2	3	4
Condition / Cause	C1	1	0	0	0
Condition / Cause	C2	0	1	0	0
Condition / Cause	C3	0	0	1	1
Condition / Cause	C4	1	0	0	0
Condition / Cause	C5	0	1	1	0
Condition / Cause	C6	0	0	0	1
Action / Effect	E1	X	–	–	–
Action / Effect	E2	–	X	–	–
Action / Effect	E3	–	–	X	–
Action / Effect	E4	–	–	–	X

That is, if C1 and C4 are 1 (or true) then the effect (or action) is E1. Similarly, if C2 and C5 is 1 (or true), action to be taken is E2 and so on.

Step 4. Since there are 4 rules in our decision table above, so we must have at least 4 test cases to test this system using this technique.

These test cases can be

1. Salary = 20,000, Expenses = 2000.
2. Salary = 1,00,000, Expenses = 10,000
3. Salary = 3,00,000, Expenses = 20,000
4. Salary = 3,00,000, Expenses = 50,000.

Thus we can say that a decision table is used to derive the test cases which can also take into account the boundary values.

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