(I am re-asking this question here, as I was informed that it was off-topic on Stack Overflow)

My interest in this question stems from concern over the lack of a license in a testing framework I came across (make-it-easy). My worry was that the lack of a license in this case would leave my (proprietary) distributed production code vulnerable to legal hassle (though I recognize this is unlikely).

However, this concern led to the following question: do the licenses on open-source testing libraries (e.g. JUnit) even apply to the production code that is tested using them? After all, that code will not be distributed with any dependencies on the testing libraries.

In Googling and searching Stack Exchange I have not found a definitive answer to this. It seems as if everyone is working under the assumption that the licenses do indeed cover that production code, but I would like a definitive answer and an explanation of that answer.

  • 2
    Related: Implications of using GPL licenced code only during testing (this might be less specific, though)
    – apsillers
    Oct 24, 2018 at 17:45
  • @apsillers The accepted answer on that question is very helpful. Do you think that that GPL-specific answer is also more widely generalizable? Oct 24, 2018 at 17:51
  • 2
    Yes -- really when we ask "do I need to satisfy GPL requirements?" we're really asking "does this use require copyright permission from the author?" which generalizes to many situations. By "this question is less specific" I meant that that question does into much more detail about what their testing environment looks like, relative to their released code. A project that didn't match that question's setup might get a different answer, perhaps.
    – apsillers
    Oct 24, 2018 at 18:11
  • 1
    What is the license for the test library? If it is GPL, for example, the GPL specifically gives you permission to copy and use it for any purpose. The fact that you used a test library to test your program does not affect your program's license, for the same reason that the fact that I used Microsoft Word to write and spellcheck my book does not pose any requirements on how I license my book. Of course, if you want to redistribute (derivatives of) Microsoft Word or (derivatives of) the test library, you need a license to do that.
    – Brandin
    Oct 25, 2018 at 4:42
  • 1
    "[my] concern over the lack of a license in a testing framework I came across" - Depending on how it was distributed, there was likely a license that you just didn't see. For example if I give you a USB key with software I wrote and say "install this onto your computer and use it" that is a license to make a copy onto your computer; I don't need to put that in writing. If I post it on GitHub, but say nothing about a license, then according to the GitHub TOS I have already given visitors of GitHub at minimum an implied license to copy from my repository into their own (i.e. 'fork').
    – Brandin
    Oct 25, 2018 at 4:55

2 Answers 2


You are right to be worried, but for the wrong reason.

If you are using testing code that has no license, merely using it can be in violation of the author's copyright (since you have to download it and make several copies). While unlikely, you could be sued for this at any point down the line.

Never use code from repos that doesn't include a license.

Only one current license, the SSPL, purports to extend to code tested using SSPL code. Note that the SSPL has not been certified by the OSI (or any other organization) as an open source license, and this is one of the reasons why some argue it shouldn't be.

  • Yeah, the "violation of the author's copyright" was what I meant by "legal hassle". I'll have to keep that in mind in the future. Thanks for the answer. Oct 24, 2018 at 18:07
  • Do you have a citation for the claim that downloading a work and making ordinary use of it isn't fair use under US law? That seems like an extraordinary claim to me. And how would we avoid downloading works other than perhaps not browsing the Internet. (Uploading it and doing things that aren't within the scope of ordinary use, of course, is a different story.) Oct 24, 2018 at 22:04
  • You missed the phrase "... and make several copies". Also, not a lawyer. Oct 25, 2018 at 3:01
  • Why would simply using some software imply that you need to "make several copies"? You should distinguish between "use" (as in make use of) and "redistribute" (as in copy and redistribute). If you see some software on a Web site for example, and it says "download" or "install" etc. that is already a license to download (i.e. copy onto your computer), but it is obviously not a license to make copies to your friends, to incorporate it into your product and redistribute that, and so on.
    – Brandin
    Oct 26, 2018 at 5:07
  • Brandin: I'll have to take your word that seeing "download" conveys a license; I'm not an attorney. However, many sources of software, particularly Github, are not labelled "download" or "install". Indeed, many people use Github for private development. So I'd want some solid legal backing before I assumed there was an implicit license. Oct 27, 2018 at 1:33

To answer you question, then answer this one.

Do the licenses on proprietary testing libraries (e.g. …) even apply to the production code that is tested using them?

So the answer to the above is yes (but probably not), however such a clause in a licence may be in violation of the non-discrimination clause of the Free Software definition. So the licence would not be a Free Software licence.

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