In game making project, client wants to make the game of which the duration is short. Is the requirement, "the duration of the game should be short", non functional requirement? or functional requirement?

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    Does this answer your question? Functional or non-functional requirement?
    – gnat
    Commented Apr 14, 2020 at 13:13
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    It's not even a requirement; it's a "wish." A requirement is something that can be definitively testable to see if the requirement has been met. Something like "the duration of the game shall be no more than five minutes." Commented Apr 14, 2020 at 13:28

1 Answer 1


If the game had a timer that could be tested specifically, it would be a functional requirement.

If it's just "an average game should take no more than a minute" it's a non-functional requirement because there isn't a single function of the code that set the game length, but the game can still pass or fail.

"Short" isn't testable because it's undefined.

  • What does it mean to "test" a requirement? It seems to me that there is a danger of arguing that functional requirements are requirements of design which can be implemented and evaluated in mindless ways, and the non-functional requirements are all the important requirements which actually determine whether the system works (and whether a functional requirement is required, or whether it should be reworked or jettisoned). Put another way is that functional requirements in this schema are a form of non-software implementation, from which a software implementation will be derived mindlessly.
    – Steve
    Commented Apr 14, 2020 at 14:41
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    @Steve: A requirement is testable if someone other than the author can objectively tell if the requirement is fulfilled or not. It essentially means that any vagueness is taken out of the requirements. Commented Apr 14, 2020 at 15:12
  • @BartVanIngenSchenau, the great irony of taking vagueness out, is that nobody has an objective test of whether something is vague or not. It seems to me that the only relevant distinction in requirements, is the greater or lesser degree to which they define implementation details, and correspondingly, the greater or lesser degree to which employing them as tests of quality becomes more and more spurious. Not everything that can be counted, counts.
    – Steve
    Commented Apr 14, 2020 at 17:09
  • @Steve it’s testable if the product owner says it passes. ;) Commented Apr 15, 2020 at 5:02
  • @candied_orange, but you're not explicitly acknowledging that you're engaged in wordplay and magicianship. The product owner is equally capable of testing the "non-functional requirements" - such as whether the game is "short" or not. This is why I argue that the true nature of the distinction here is nothing to do with testability, functionality, or objectivity - the distinction is the degree to which the requirements define a specific implementation. The task of the person drafting the "functional requirements", is to design a system that implements the real requirements.
    – Steve
    Commented Apr 15, 2020 at 12:28

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