How to test a function created with intern in clojure?

Question

I use "intern" function for generate runtime funtions, but I can't test generted function.

In core.clj I defined functions that generate runtime functions like this.

(ns cftf.core)

(defn- generation-function [function-name ratio]
  (let [function-symbol        (symbol function-name)]
    (intern 'cftf.core function-symbol (fn [input] (cftf.core/convert ratio input)))))

...

(defn generate-function-by-units [units]
  (->> units
       (units->function-name-and-ratio)
       (map #(generation-function (first %) (second %)))))

I wrote the following test code.

(ns cftf.core-test
  (:require [clojure.test :refer :all]
            [cftf.core :as c]))


(defn amount-of-alcohol-per-one-bottle [bottle-size abv]
  (* bottle-size (/ abv 100)))

(def alcohol-units
  {:soju (amount-of-alcohol-per-one-bottle 360 16.5)
   :beer (amount-of-alcohol-per-one-bottle 500 5)
   :whisky (amount-of-alcohol-per-one-bottle 700 40)
   })

(c/generate-function-by-units alcohol-units)

(deftest a-test
  (testing "soju->beer test"
    (is (= (int (c/soju->beer 1)) 2))))

After calling "generate-function-by-units" in the repl, you can use the "soju->beer" function.

But in the test I get the error "No such var: c/soju->beer".

I've tried using a fixture or calling " generate-function-by-units" the top in test.clj, but I'm still getting the error.