Testing private functions in Clojure

Let’s suppose there’s this function:

;; src/mypackage.clj
(ns mypackage)

(defn- my-private-function
  [x]
  ;; For simplicity, just return the input
  x)

You can test it like this:

;; test/mypackage_test.clj
(ns mypackage-test
  (:require [mypackage :as p]))

(deftest test-my-package
  (let [function-to-test (var p/my-private-function)]
  
    (testing "happy path"
      (is (= 42 (function-to-test 42))))))