renames_spec.clj

;; see also https://twitter.com/thing_umbrella/status/1111427898487898113
(require '[clojure.spec.alpha :as s])

;; spec that ensures the keys in renames match the keys in map
(s/def ::rename-keys-args
  (s/and (s/cat :map map? :renames map?)
         (fn [{:keys [map renames]}]
           (every? map (keys renames)))))

;; ok
(s/explain ::rename-keys-args [{:a 1} {:a 2}])

;; error
(s/explain ::rename-keys-args [{:a 1} {:b 2}])