Why should I consider BB testing?
The main and original purpose why Black Box testing, as a process, is being performed is to make sure users will receive high quality solutions that will be operating fine in their own system environments. That is quite important as the more users are into your application the more devices, Oss, etc., they will be running your app on.
To make long things short here are some reasons for you to consider BB testing as a planned activity. Basically BB Testing is great for determining if UI as well as user inputs/outputs are working the way they were meant to. This part is fitting greatly within system as well as functional testing.
Can’t I just pass with my White Box tests?
Surely one may say that each module’s function has already been tested within unit tests. And that would be a part of what is called White Box testing, right? But this step is usually committed by programmers, not QA. That’s where the catch is hiding. If we are talking requirements docs now then all modules may be considered working correctly after tests were run and the results were satisfying. But does that truly mean all is working correctly? Only to some extent.
Such tests are proving every module is working correctly as a separate peace. WB testing is verifying the code, not the app. But in reality it’s the functional testing what determines hos solid is the application when all modules are put together. The very best way to perform such testing is when it is done from external perspective, or in other words in a way the solution will be used by your loving end user that will not be referring to the application’s code.
Wait! It’s expensive as I will be spending more on additional testing!
First of all one will be earning less if his software is not used. And you will be spending a lot of money on maintenance, fixes and patches. BB testing is a great mean of achieving quality as long as all’s done by QA specialist who had no relation to the development process.