I'm trying to pass :gen overrides for clojure.spec.test.alpha/check, but I get the sense my understanding of the documentation.

I expected the following to succeed:

(defn foo [k]
  (if (keyword? k) :k :nope))

(def my-kw? (partial instance? Keyword))

(s/fdef foo
        :args (s/cat :a-keyword my-kw?)
        :ret #{:k})

(spec.test/check `foo {:gen {`my-kw? (gen/return :kw)}})

I'm trying to pass in a generator for the my-kw? spec, but it fails with the cause "Unable to construct gen at: [:a-keyword] for: my-kw?"

Is overriding generators on the call to check possible and I'm getting some detail wrong, or did I just misunderstand the docs for check and there is no way to override generators like that?

the values in that map should be 0-arg functions returning a generator

so change (gen/return :kw) to #(gen/return :kw)

although now that I back up a bit, I don’t think you can do what you’re trying to do with my-kw? either

you should instead register a named spec instead of my-kw?:

(s/def ::my-kw keyword?) and then use ::my-kw instead of my-kw? and as the key in the gen map

Putting it all together:

user=> (require '[clojure.spec.alpha :as s] [clojure.spec.test.alpha :as stest] [clojure.spec.gen.alpha :as gen])
nil
user=> (defn foo [k] (if (keyword? k) :k :nope))
#'user/foo
user=> (s/def ::my-kw keyword?)
:user/my-kw
user=> (s/fdef foo :args (s/cat :a-keyword ::my-kw) :ret #{:k})
user/foo
user=> (stest/check `foo {:gen {::my-kw #(gen/return :kw)}})
({:spec #object[clojure.spec.alpha$fspec_impl$reify__2451 0x6c25e6c4 "clojure.spec.alpha$fspec_impl$reify__2451@6c25e6c4"], :clojure.spec.test.check/ret {:result true, :num-tests 1000, :seed 1517344332731}, :sym user/foo})

hey all, I've been meddling with spec and I came across something I don't know how to represent. I want to create a spec for the s/keys spec itself and I have this:

(s/cat :spec-kind #{`s/keys}
         :keys      (s/+ (s/cat :mandatory+qualified? #{:req :opt :req-un :opt-un}
                                :keys                 (s/coll-of keyword? :kind vector?))))

keys*

great, thanks! missed that when looking through the api

I'm running into the same wall described at https://groups.google.com/d/msg/clojure/i8Rz-AnCoa8/OEg04fbKBwAJ where we'd like to resolve a symbol for a multi-fn in clojurescript but apparently cannot. is this being looked into? that thread died.