Heard of decision table testing before? This concept is rarely heard since it is not used by the testers very often. This article is
focussed upon the decision table testing and when it is used.
"Decision table testing proves to be a very handy software
testing methodology which comes to the tester’s rescue whenever a combination
of inputs is to be dealt with and different results are produced".
To understand
this concept you can take example of two binary inputs A and B. You will get 4
different combinations of these two inputs which will produce 4 different
results based up on whatever operation is performed on them. If you observe
some of these outputs to be the same, then you can select any of them and the
output which is different for testing.
With a small number of inputs you won’t
realise the importance of this testing technique since you will feel like using
a normal testing technique. But with a large number of inputs, the significance
of the decision table testing becomes quite clear. The below mentioned
expression gives the possible number of combinations of the inputs:
2^n, where n stands for the number of inputs.
Let us
take n=10. The number of possible input combinations comes as 1024!
What is Decision Table Testing?
- Decision table is actually a table that showcases all
the different possible combinations of the supplied inputs along with their
corresponding outputs.
- Decision table testing is one of the black box testing
techniques.
- This testing technique is widely used in web applications however;
it has got limited scope when it comes to equivalence partitioning and boundary
value analysis.
- In boundary value analysis and equivalence partitioning, the
decision table testing can be applied only in specific conditions.
- Mostly, decision table testing is used for testing rules and logics.
- Sometimes, it is
also used to evaluate complex business rules.
- These complex rules are broken
down in to simple decision tables.
Advantages of Decision Table Testing
Below mentioned are some of the advantages
of the decision table testing:
- With decision table testing you get a frame work that
facilitates complete and accurate processing of the rules and logics.
- Decision table testing helps in the identification of
the test scenarios faster because of its simple and accurate tabular
representations.
- Decision tables are quite easy to understand.
- Decision tables require less maintenance and updating
the contents is also very easy.
- With a decision table you can verify whether or not you
have checked all the possible test combinations.
What portions are defined for decision table testing?
- Out of
all the black box testing methods, decision table testing is quite rigorous.
- But
nonetheless, decision tables provide quite a compact and precise way for
modelling a complex logic.
- Below mentioned 4 portions have been defined for a
typical decision table:
- Stub portion,
- Entry portion,
- Condition portion, and
lastly
- Action portion.
- “Rule” is
the column in entry portion and indicates which actions are to be taken for the
condition that is indicated in the condition portion of the table.
- In some
decision tables all the conditions are binary, such kind of decision tables are
called “limited entry decision tables”.
- On the contrary, if the conditions have
several values, such a table is known as
“extended entry decision table”.
There is one disadvantage of decision table testing:
It is very difficult to scale up the decision tables.
