I think it doesn’t know how to generate a ratom from a predicate.

Maybe you should try making ::ratom with it’s own with-gen so that this with-gen also determines the contents of the ratom.

ahh, ofcourse. Thank you @borkdude

fails with the same message

@hkjels I made a small example in JVM Clojure which should be straightforward to port to cljs:

(s/def ::ratom
  (s/with-gen #(instance? clojure.lang.IAtom %)
    #(gen/fmap atom (gen/string-alphanumeric))))

(gen/sample (s/gen ::ratom))

;; (#atom["" 0x6ff87e8] #atom["" 0x710f246c] #atom["7" 0x43b11d93] #atom["N" 0x6fd3f101] #atom["k6" 0x15e9ebd4] #atom["xFdxB" 0x1dcd8141] #atom["" 0x56db5aee] #atom["J7" 0x26f0f2cd] #atom["67Pzk94" 0x7c1d0a8c] #atom["e" 0xdab4bc7])

(set? (deref %)) is what causes it to fail. I’ll digg a little further

@hkjels

(s/def ::set-ratom
  (s/with-gen (s/and #(instance? clojure.lang.IAtom %)
                     (fn [a]
                       (set? @a)))
    #(gen/fmap atom (gen/fmap set (gen/string-alphanumeric)))))

@hkjels You can check with gen/sample

(s/def ::id string?)
(s/def ::value string?)
(s/def ::label string?)

(s/def ::item (s/keys :req-un [::id ::value] :opt-un [::label]))

(s/def ::items
  (s/coll-of ::item :kind? set))

(take 2 (gen/sample (s/gen ::items))) ([{:id "", :value ""} {:id "", :value "", :label ""} {:id "", :value ""} {:id "", :value ""} {:id "", :value ""}] [{:id "", :value "", :label ""} {:id "", :value "6"} {:id "E", :value "2", :label ""} {:id "", :value "", :label "w"}])

Don’t know if this is a bug or by design. Alex probably knows

@hkjels This is a workaround. Not pretty, but it works:

(s/def ::items
  (s/with-gen
    (s/coll-of ::item :kind? set)
    #(gen/fmap set (s/gen (s/coll-of ::item)))))

hey, that works

hmm, weird that (s/coll-of ::item :kind? set) does not return a set

that must be a bug right?

Don’t know. I’m sure Alex will reply later today

Thank you!

@hkjels use a predicate like everything else: (s/coll-of ::item :kind set?)

ahh, ok

and it’s :kind, not :kind?:

ahh, that explains why it didn’t barf

🙂

yeah, would be nice if it told you

ah I wasn’t awake enough to spot those typos 🙂

I like it how spec lets you specify things gradually or as fine-grained as you want

My google-fu is failing me: I want to write a spec for a function that takes an atom (actually a Reagent atom). Is there a way to do that?

@manutter51 Maybe this helps: https://clojurians.slack.com/archives/C1B1BB2Q3/p1522140603000191

@manutter51 replace the exact type with something from here: https://github.com/reagent-project/reagent/blob/master/src/reagent/ratom.cljs#L121

but IAtom will also do, but not specific to Reagent

(s/def :test/ratom? #(instance? reagent.ratom/RAtom %))
(s/valid? :test/ratom? 1) ; false
(s/valid? :test/ratom? (r/atom nil)) ; true

Thanks much, I’ll see if I can get that to work. The tricky part is this all has to work in CLJS, but I want to match both regular atoms and Reagent atoms so I can pass in test dummies

then IAtom seems the right abstraction

Arguably, testing anything more than the class isn’t very useful, but YMMV

(I mean, testing the interface may be useful too, but the contents, maybe not so much)

yes, you can just as well create ratom dummies, so it’s a good question why you want to do that

The advice I remember is that spec is mostly useful for testing values. Testing references is likely less useful

since testing the reference at any point in time doesn’t say much about what it will become at any point in the future

it might be more useful to spec the functions that mutate that reference, or, say, use spec in a validator

Yeah, that’s a good point, I could just use ratoms everywhere

That’s probably the best solution — tks much