Fizz Buzz Kata in Clojure

Up and Running

You are familar with counting/dividing game Fizz Buzz.

You have Leiningen installed

Create a new project

%> lein new fizzbuzz
%> cd fizzbuzz

To run tests add plugin lein-test-refresh by adding :plugins to project.clj:

(defproject fizzbuzz "0.1.0-SNAPSHOT"
  :description "FIXME: write description"
  :url "http://example.com/FIXME"
  :license {:name "Eclipse Public License"
            :url "http://www.eclipse.org/legal/epl-v10.html"}
  :dependencies [[org.clojure/clojure "1.5.1"]]
  :plugins [[com.jakemccrary/lein-test-refresh "0.1.2"]])

Now we run our tests

%> lein test-refresh

You should see the dummy test fail.

Editor: You may like LightTable but you can use any editor for this exercise.

Clojure cheat sheet

Your First Test

Replace the first dummy test with the following in test/fizzbuzz/core_test.clj

(deftest one-should-be-one
  (is (= "1" (fizz-buzz 1))))

Make it pass by replacing the dummy code with the following in src/fizzbuz/core.clj

(defn fizz-buzz [x]
  (str 1))

Second Test

We could refactor out the subtle duplication between the test and code. Naw, I'll just triangulate.

(deftest two-should-be-two
  (is (= "2" (fizz-buzz 2))))

And to make it pass one small change

(defn fizz-buzz [x]
  (str x))

Test 3

(deftest three-should-fizz
  (is (= "Fizz" (fizz-buzz 3))))

Passing

(defn fizz-buzz [x]
  (if (zero? (mod x 3)) 
    "Fizz"
    (str x)))

Divisible by Five is 'Buzz'

We are skipping testing for 4 because it doesn't add anything.

(deftest five-should-buzz
  (is (= "Buzz" (fizz-buzz 5))))

And passing

(defn fizz-buzz [x]
  (if (zero? (mod x 3)) 
    "Fizz"
    (if (zero? (mod x 5))
      "Buzz"
      (str x))))

Test for 6

(deftest six-should-fizz
  (is (= "Fizz" (fizz-buzz 6))))

Which we expect to pass.

What? It passed?

Test for 15

(deftest fifteen-should-fizz-buzz
  (is (= "FizzBuzz" (fizz-buzz 15))))

Passing

(defn fizz-buzz [x]
  (cond
    (zero? (mod x 15)) "FizzBuzz"
    (zero? (mod x 3)) "Fizz"
    (zero? (mod x 5)) "Buzz"
    :else (str x)))

Count to 100

(deftest sequence-fizz-buzz
  (is (= '("1" "2" "Fizz" "4" "Buzz") (fizz-buzz-seq 1 5))))

Passing

(defn fizz-buzz-seq [from to]
  (map fizz-buzz (range from (inc to))))

Finished! It is time for a cookie!

You may want to move on to the banking exercise.