Haskell FizzBuzz

FizzBuzz.hs

module FizzBuzz (main, fizzBuzz) where

import Data.Foldable
import Data.Maybe

isMultipleOf :: Int -> Int -> Bool
n `isMultipleOf` f = n `mod` f == 0

fizzBuzz :: Int -> String
fizzBuzz x = fromMaybe (show x) (fold rules x)
  where
    rules = [
                (`isMultipleOf` 3) ~> "Fizz",
                (`isMultipleOf` 5) ~> "Buzz"
            ]
    rule ~> result = \n -> if rule n then Just result else Nothing

main :: IO ()
main = mapM_ putStrLn $ map fizzBuzz [1..100]

FizzBuzzSpec.hs

module FizzBuzzSpec (main) where

import FizzBuzz (fizzBuzz)
import Test.Hspec

main :: IO ()
main = hspec $ do
    describe "FizzBuzz" $ do
        it "should return \"1\" when given 1" $ do
            fizzBuzz 1 `shouldBe` "1"
        it "should return \"2\" when given 2" $ do
            fizzBuzz 2 `shouldBe` "2"
        it "should return \"4\" when given 4" $ do
            fizzBuzz 4 `shouldBe` "4"
        it "should return \"Fizz\" when given 3" $ do
            fizzBuzz 3 `shouldBe` "Fizz"
        it "should return \"Fizz\" when given 6" $ do
            fizzBuzz 6 `shouldBe` "Fizz"
        it "should return \"Fizz\" when given 9" $ do
            fizzBuzz 9 `shouldBe` "Fizz"
        it "should return \"Buzz\" when given 5" $ do
            fizzBuzz 5 `shouldBe` "Buzz"
        it "should return \"Buzz\" when given 10" $ do
            fizzBuzz 10 `shouldBe` "Buzz"
        it "should return \"Buzz\" when given 20" $ do
            fizzBuzz 20 `shouldBe` "Buzz"
        it "should return \"FizzBuzz\" when given 15" $ do
            fizzBuzz 15 `shouldBe` "FizzBuzz"
        it "should return`\"FizzBuzz\" when given 30" $ do
            fizzBuzz 30 `shouldBe` "FizzBuzz"
        it "should return`\"FizzBuzz\" when given 45" $ do
            fizzBuzz 45 `shouldBe` "FizzBuzz"