Black Box Testing Technique : Decision Table Testing

Black Box Testing Technique

If I would like to execute testing a software (testing web or windows application), I start with thinking about how to select the test cases. If I have no idea about software's internal algorithm and cannot cover all combinations of input values and preconditions for a module of software because of resource constraint (Time or manpower), I will use Black Box Testing Technique to design the input values.

Decision Table Testing

Decision Table Testing is a software testing technique that tries to create the complete test cases by using decision table. This decision table will contain all possible values of each input and output. Then, we mark each possible scenario to that decision table.

Example

System: Fund Transfer feature in ATM system of A Bank with 2 possible inputs and 1 possible output:
1st input: How to transfer
- A Bank to A Bank
- A Bank to B Bank
2nd input: Amount of money
- Less than $1.00
- Between $1.00 and $5,000
- More than $5,000

1st output: Fee
- Fee is not charged
- $2.00 is charged

After reviewing the requirement, the scenario may be as below.
1) Transfer from A Bank to A Bank. There is no charge.
2) Transfer from A Bank to B Bank less than or equal to $5,000. There is no charge.
3) Transfer from A Bank to B Bank more than $5,000. $2.00 is charged.

Map them to Decision Table. Now we can check if all possible cases have been derived from requirement. If not, we need to review them again.

----------------------------------------------------------

Now you can design and execute testing a software (testing web or windows application) by using Decision Table testing technique. 

Posted in: Test Design Technique