Testing without functional specifications?

How often does it happen that the tester is asked to test without any functional specifications (test basis). And unfortunately, we see too often that the tester simply agrees and starts testing the system under test. But is this really possible? Taking into consideration the definition of functional testing, the answer is obvious. Functional testing is nothing more than comparing the test basis with the test object. After comparing, the tester can give insight into the different between the test basis and the test object (=quality). Thus, without a test basis testing is not possible. This is because there is nothing to compare!

So to be clear, never just accept a test project where there is a lack of or incomplete functional specifications. In this case try to convince the client with an explanation of the definition of testing. And explain that there is nothing to compare when the test basis is missing. The same applies if the test object is missing.

How can the tester know if something conforms to the wishes of the client? After all, this wish (functional specifications) is not written down. Maybe the client wishes that after you press the enter button, the system must go up in smoke. You as a tester will notify the result as a bug, but the test conforms 100% the client wishes, thus OK.

This shows that as a tester you can never judge whether a test is OK or NOK without having a reference. The client will understand this too and this will change his opinion about the importancy of specifying the functionality.

In fact, having a reference is not only necessary for the purpose of testing, but also for the benefit of developing the test object. If nothing has been described how does the developer knows what he needs to built? Of course we as testers can help the client to develop the functional specifications. And for this Model Based Testing can be perfectly used. The tester will draw the desired functionality in a graphic model. Such a graphic model is readable for everyone in the project and can later be used to derive the test cases.

Drawing the test model often happens step by step because during this process the client will be encouraged to think more in detail. It is like the functionality then comes to life. Once the test model is complete, it can be used by the tester in order to generate the test cases including the expected test results, by using the ‘easy to use’ DTM tool.

Here we see that Model Based Testing is more then just generating the test cases out of an test model. Model Based Testing is also a way to help the customer in getting insight into the business case. With this we also see that testing has shifted to the start of the project and not, as so often happened, it is done at the end!

Silvio Cacace, Productmanager DTMtool – XL Family