> I'm sure this was considered
Indeed, and when clojure.spec was first introduced, instrument did check :ret and :fn specs. That feature was deliberately removed and the reason for it is (paraphrased): * clojure.spec/instrument helps check that your functions are _called_ correctly * clojure.spec.test/check helps check that your functions are _implemented_ correctly Those are two different concerns and they should not be complected into one function. The argument checks performed by instrument are straightforward: are the arguments valid? The function invariant is checked by performing generative testing. See this thread for some of the discussion around this (and Rich has also discussed in on Slack quite a bit): https://groups.google.com/d/topic/clojure/RLQBFJ0vGG4/discussion Sean Corfield -- (970) FOR-SEAN -- (904) 302-SEAN An Architect's View -- http://corfield.org/ "If you're not annoying somebody, you're not really alive." -- Margaret Atwood On 8/6/16, 10:02 AM, "Tom Connors" <clojure@googlegroups.com on behalf of t.v.conn...@gmail.com> wrote: spec.test/instrument doesn't check the return value of spec'd functions and according to the spec guide this is because we should be checking function implementations at testing time, not development time. It seems to me that adding :ret and :fn checks to instrumented functions would be worthwhile even though tests are a better place to do those checks - since instrumentation is meant to be turned off in production the performance hit doesn't matter, and since we're already verifying that the arguments conform to spec, why not check the return value as well? A benefit would be that if we haven't yet written (or won't write) generators and tests, we still get a confidence increase about our instrumented functions' return values. I'm sure this was considered, so I'm just wondering if "do that in your tests" is the entire reason for this design choice. -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
