Non-functional testing

We learned a lot about functional requirements and automated acceptance testing in the previous chapters. But what should we do with non-functional requirements? Or even more challenging, what if there are no requirements? Should we skip them in the CD process? We will answer these questions throughout this section.

Non-functional aspects of the software are always important because they can cause a significant risk to how the system operates.

For example, many applications fail because they are unable to bear the load of a sudden increase in the number of users. In one of his books, Jakob Nielsen writes about the user experience that 1 second is about the limit for the user's flow of thought to stay uninterrupted. Imagine that our system, with its growing load, starts to exceed that limit. Users may stop using the service just because of its performance. Taking this into consideration, non-functional testing is just...