Starting with Clojure Testing

  • Prereq Leiningen

I have to admit, I was a little stubborn towards Clojure when I first started working with it for my job. What sold me was how easy it was to create a sandbox with bundled testing so you can test your functions in peace (haven't gotten a spark for REPL driven development yet). Here is how I would convince someone to be a little friendlier towards Clojure -testing with clj-test has been quite enjoyable!

Enter in the command line:

  1. lein new <project-name> : this will use the default project template from lein that includes a whole test setup with clj-test
  2. cd into that directory and run lein test -you will get an error on purpose. Sounds like a case for TDD (Test Driven Development)!


lein test tester.core-test

lein test :only tester.core-test/a-test

FAIL in (a-test) (core_test.clj:7)
FIXME, I fail.
expected: (= 0 1)
  actual: (not (= 0 1))
  1. Fix the test! You'll just need to make a change in src/core.clj.
  2. The fun part will be adding more organized code and their respective unit tests. This will just be a review of how to import namespaces so you can access appropriate code in the unit tests you'll write. The structure goes:
  3. With every new subfolder in the src code folder, define namespaces as: (ns <app-name>.<folder name>.<filename>) e.g. (ns clj-testing.utils.numbers) : created a utils folder in src and a file numbers.clj
  4. Import that namespace and add an appropriate unit test:
(ns clj-testing.utils.numbers-test
(:require [clojure.test :refer :all]
          [clj-testing.util.numbers :as num])) 
(deftest test-parseInt
  (testing "Parses string to int"
    (is (= -24 (num/parse-int "-24")))))