paths.cljs

(ns vidiot.listener.paths
  (:require
   [cljs.spec :as s]
   [cljs.spec.impl.gen :as gen]
   [cljs.spec.test :as stest]))


(def path (s/coll-of (s/with-gen string? #(s/gen #{"a" "b" "c" "d"}))
                     :min-count 1
                     :kind vector?
                     :into []))

(s/def ::path
  (s/with-gen
    path
    (fn [] (gen/fmap #(vec (take 5 %)) (s/gen path)))))

(defn subpaths [xs]
  (-> (reductions conj [] xs) rest))

(s/fdef subpaths
        :args (s/cat :xs ::path)
        :ret seq?
        :fn (s/and
             (s/coll-of ::path)
             #(= (-> % :args :xs count) (-> % :ret count))))

> (stest/summarize-results (stest/check `subpaths))
{:spec
 (fspec
  :args
  (cat :xs :vidiot.listener.paths/path)
  :ret
  seq?
  :fn
  (and
   (coll-of :vidiot.listener.paths/path)
   (fn*
    [p1__38761#]
    (= (-> p1__38761# :args :xs count) (-> p1__38761# :ret count))))),
 :sym vidiot.listener.paths/subpaths,
 :failure
 {:cljs.spec/problems
  ({:path [:fn],
    :pred :cljs.spec/unknown,
    :val :args,
    :via [:vidiot.listener.paths/path],
    :in [0 0]}
   {:path [:fn],
    :pred :cljs.spec/unknown,
    :val {:xs ["d"]},
    :via [:vidiot.listener.paths/path],
    :in [0 1]}
   {:path [:fn],
    :pred :cljs.spec/unknown,
    :val :ret,
    :via [:vidiot.listener.paths/path],
    :in [1 0]}
   {:path [:fn],
    :pred :cljs.spec/unknown,
    :val (["d"]),
    :via [:vidiot.listener.paths/path],
    :in [1 1]}),
  :cljs.spec.test/args (["d"]),
  :cljs.spec.test/val {:args {:xs ["d"]}, :ret (["d"])},
  :cljs.spec/failure :check-failed}}
{:total 1, :check-failed 1}

;; So that fails, let us re-fdef subpaths.
;; (I have moved `(s/coll-of ::path)` into the :ret)
(s/fdef subpaths
        :args (s/cat :xs ::path)
        :ret (s/coll-of ::path)
        :fn (s/and
             #(= (-> % :args :xs count) (-> % :ret count))))

> (stest/summarize-results (stest/check `subpaths))
{:sym vidiot.listener.paths/subpaths}
{:total 1, :check-passed 1}

;; Why does this only work when I place it in the `:ret`?