VCR in Clojure

core.clj

(ns example.core
  (:require [vcr-clj.core :as vcr]
            [vcr-clj.clj-http :as vcr-http]
            [clj-http.client :as client]))

(defn random [n]
  {:number (+ 10 (rand-int n))
   :username "admin"
   :password "Lol, Ima Password!"})

(defn keep-only-uri [params]
  (select-keys params [:uri]))

(time
 (vcr-http/with-cassette {:name :http/random
                          :arg-key-fn keep-only-uri}
   (:body
    (client/get "https://www.random.org/integers/?num=1&min=1&max=100&col=1&base=10&format=plain&rnd=new"))))

core_test.clj

(ns example.core-test
  (:require [clojure.test :refer :all]
            [example.core :as ex]
            [vcr-clj.core :as vcr]))

(defn remove-password [ret]
  (assoc ret :password :REDACTED))

(defn- anom-params [n]
  :REDACTED)

(deftest test-random-function
  (testing "gets a random fn"
    (vcr/with-cassette
      {:name :random/numbers}
      [{:var #'ex/random :arg-key-fn anom-params :return-transformer remove-password}]
      (is (= 89 (:number (ex/random 90)))))))

(defn only-types [ret]
  (->> ret
       (map #(update % 1 type))
       (into {})))

(deftest test-random-fn-schema
  (vcr/with-cassette
    {:name :random/numbers-schema}
    [{:var #'ex/random :arg-key-fn anom-params :return-transformer only-types}]
    (is (= {:username Long
            :password String
            :number Long}
           (ex/random 90)))))

project.clj

(defproject example "0.1.0-SNAPSHOT"
  :description "FIXME: write description"
  :url "http://example.com/FIXME"
  :license {:name "EPL-2.0 OR GPL-2.0-or-later WITH Classpath-exception-2.0"
            :url "https://www.eclipse.org/legal/epl-2.0/"}
  :dependencies [[org.clojure/clojure "1.10.1"]
                 [com.gfredericks/vcr-clj "0.4.19"]
                 [clj-http "3.10.3"]]

  :repl-options {:init-ns example.core})