Can be done by adding subdirectory with tests, and embedding them in the lens tests by means of hs-subdirectories or such.
For such a package to be valuable, the tests would also have to be more complete and give a certain amount of certainty that if something passes isTraversal, it really is a traversal.
The current plan is that for 3.8:
Then the user can import Control.Lens.Properties from lens-properties if they want to get the QuickCheck or HSpec plumbing, and we don't have to incur the dependencies in the main package.
We'd then distribute lens-properties/* as part of the main lens.cabal distribution as well as a separate package that we update periodically.
Note: @dag converted tests/properties over to test-framework in #191.
I have started some work in this at https://github.com/ocharles/lens/tree/lens-properties. It seems to work; it still needs documentation for 'isIso' and 'isPrism', and someone needs to check this is actually the right solution :)
Also, cabal init gave me copyright in the license, but I'm unsure what to do with that. If Edward or someone else would rather have the copyright (after all, I just shuffled code around) I am fine with that.
@ocharles Would you feel up to updating this patch to work with 3.9 or 3.10?
I think a week has passed now. #377 opened, lets get this done! Please review and let me know what more needs to be done on the pull request.
Yay! Will do.