fizzbuzz.hs

import Test.Hspec

main = hspec $ do
  describe "fizbuzz" $ do
    it "returns a number string when given a number" $ do
      fb 1 `shouldBe` "1"
      fb 2 `shouldBe` "2"
      fb 4 `shouldBe` "4"
    it "returns 'fizz' when given a multiple of 3" $ do
      fb 3 `shouldBe` "fizz"
      fb 6 `shouldBe` "fizz"
    it "returns 'buzz' when given a multiple of 5" $ do
      fb 5 `shouldBe` "buzz"
      fb 10 `shouldBe` "buzz"
    it "returns 'fizzbuzz' when given a multiple of 3 and 5" $ do
      fb 15 `shouldBe` "fizzbuzz"
      fb 30 `shouldBe` "fizzbuzz"

mult :: Int -> Int -> Bool
mult a x = a `mod` x == 0

fb :: Int -> String
fb a | (a `mult` 3 && a `mult` 5) = "fizzbuzz"
fb a | (a `mult` 5)               = "buzz"
fb a | (a `mult` 3)               = "fizz"
fb a                              = show a