Solving the "FizzBuzz" kata (http://codingdojo.org/cgi-bin/wiki.pl?KataFizzBuzz) in Clojure

fizzbuzz.clj

(ns fizzbuzz.core
  (:gen-class))

(defn- format-output [output current]
  (cond
    (= 0 (mod current 15)) (str output "FizzBuzz\n")
    (= 0 (mod current 3)) (str output "Fizz\n")
    (= 0 (mod current 5)) (str output "Buzz\n")
    :else (str output current "\n")))

(defn fizz-buzz-printer
  ([output current limit]
    (let [product (format-output output current)]
      (if (< current limit)
        (fizz-buzz-printer product (+ 1 current) limit)
        product)))
  ([start limit]
   (fizz-buzz-printer "" start limit))
  ([limit]
    (fizz-buzz-printer 1 limit)))

(defn -main
  [& args]
  ;; work around dangerous default behaviour in Clojure
  (alter-var-root #'*read-eval* (constantly false))
  (print (fizz-buzz-printer 100)))

fizzbuzz_test.clj

(ns fizzbuzz.core-test
  (:require [clojure.test :refer :all]
            [fizzbuzz.core :refer :all]))

(deftest fizz-buzz-printer-test
  (testing "with 1"
    (is (= "1\n" (fizz-buzz-printer 1))))
  (testing "with 2"
    (is (= "1\n2\n" (fizz-buzz-printer 2))))
  (testing "from 1-3"
    (is (= "1\n2\nFizz\n" (fizz-buzz-printer 3))))
  (testing "from 1-4"
    (is (= "1\n2\nFizz\n4\n" (fizz-buzz-printer 4))))
  (testing "from 3-4"
    (is (= "Fizz\n4\n" (fizz-buzz-printer 3 4))))
  (testing "from 4-5"
    (is (= "4\nBuzz\n" (fizz-buzz-printer 4 5))))
  (testing "from 4-6"
    (is (= "4\nBuzz\nFizz\n" (fizz-buzz-printer 4 6))))
  (testing "from 9-11"
    (is (= "Fizz\nBuzz\n11\n" (fizz-buzz-printer 9 11))))
  (testing "from 14-16"
    (is (= "14\nFizzBuzz\n16\n" (fizz-buzz-printer 14 16)))))