namespacing specs?

(ns scratch
  (:require
   [clojure.spec.alpha :as s]
   [clojure.spec.test.alpha :as stest]))

(defn lighten-color
  [{:keys [color] :as m}]
  (case color
    "RED" (assoc m :color "PINK")
    "BLUE" (assoc m :color "PERIWINKLE")
    "BLACK" (assoc m :color "GRAY")))

;; need to "namespace" color, for pre and post function
(s/def :scratch-pre/color #{"RED" "BLUE" "BLACK"})
(s/def :scratch-post/color #{"PINK" "PERIWINKLE" "GRAY"})

;; because :req-un matches keys based on name (the word(s) past /)
(s/def ::m-pre
  (s/keys :req-un [:scratch-pre/color]))

(s/def ::m-post
  (s/keys :req-un [:scratch-post/color]))

(s/fdef lighten-color
  :args (s/cat :m ::m-pre)
  :ret ::m-post)

(stest/check `lighten-color)