generative testing

count.clj

  (defn count-elements [coll1 coll2]
    (+ (count coll1) (count coll2) 1))

  (defn count-elements-tester [f]
    (let [n (rand-int 6)
          m (rand-int 6)
          output (+ n m)
          inputs [(range n) (range m)]
          actual (apply f inputs)]
      (if (= actual output)
        {:result :success}
        {:result :error :inputs inputs :output output :actual actual})))

  (filter #(-> % :result (= :error)) (map count-elements-tester (repeat 10 count-elements)))