fizzbuzz.clj

(defn divisible?
  [divisor number]
  (zero? (mod number divisor)))

(defn fizzbuzz
  [number]
  (cond (divisible? 15 number) "fizzbuzz"
        (divisible? 5 number) "buzz"
        (divisible? 3 number) "fizz"
        :else (str number)))

(deftest fizzbuzz-should
  (testing "multiples of 3 should return fizz"
    (is (= (fizzbuzz 3) "fizz"))
    (is (= (fizzbuzz 6) "fizz"))
    (is (= (fizzbuzz 9) "fizz")))
  (testing "multiples of 5 should return buzz"
    (is (= (fizzbuzz 5) "buzz"))
    (is (= (fizzbuzz 10) "buzz"))
    (is (= (fizzbuzz 20) "buzz")))
  (testing "multiples of 3 and 5 should return fizzbuzz"
    (is (= (fizzbuzz 15) "fizzbuzz"))
    (is (= (fizzbuzz 30) "fizzbuzz"))
    (is (= (fizzbuzz 45) "fizzbuzz")))
  (testing "everything else should return the original number"
    (is (= (fizzbuzz 4) "4"))
    (is (= (fizzbuzz 7) "7"))
    (is (= (fizzbuzz 11) "11"))))