We recently went over how to test our programs and code using decision table testing. Decision table testing is extremely useful for laying out the requirements and conditions so that it is easier to comprehend and understand. This blog goes over, in detail, how to set up a decision table for a problem with an ATM and what conditions must be met to withdraw money. You can find it here: http://reqtest.com/requirements-blog/a-guide-to-using-decision-tables/ (I also used their pictures.)
I chose this blog to share with you because it relates directly to the assignment we were given for decision table testing. It has a section before the steps that give you the advantages and disadvantages to using the decision table which I thought would be useful to know and highlight. It also has every step for creating a decision table and is easy to understand.
“One advantage of using decision tables is that they make it possible to detect combinations of conditions that would otherwise not have been found and therefore not tested or developed. The requirements become much clearer and you often realize that some requirements are illogical, something that is hard to see when the requirements are only expressed in text.” – Ulf Eriksson, ReQtest
This advantage to decision table testing is a big one. Being able to easily cover every single case without being confused is extremely helpful. Essentially, decision tables give you a visual to go with the words.
The disadvantage to using decision table testing is that the decision table does not represent the complete test cases. Meaning you will have to think a little harder about how you write your cases.
With this being said, decision table testing can be used anywhere and this blog stresses that the tables should be constructed during system design so that the designers and testers are able to take advantage of the tables.
The steps are pretty easy to creating a decision table, the blog goes into more details with pictures (I recommend checking it out).
First, you want to figure out the conditions and actions in your problem. Conditions will be a requirement while actions will be the thing that happens if specific requirements are fulfilled.
Second, You want to figure out how many rules you are going to have. This is found by 2^n where n is the number of conditions in your table. Your going to want to fill out your table with the different possibilities of conditions being true/false.
Third, you want to reduce your table by combining redundant cases. The “-” means that you don’t care if credit is granted sense you have enough money in your account regardless.
Notice how Column 1 and 3 were the same? Now they are combined.
This is the final table you would use to write test cases for this program! Overall, Decision Table Testing is a great way to lay out all requirements in front of you to ensure you do not miss any possible combinations of input!