Dojo

Test.hs

import Test.Hspec


-- ## Prerequisite
-- 
-- $ brew install ghc
-- $ cabal update
-- $ cabal install hspec

-- ## Running
--
-- $ runhaskell Test.hs

-- ## Mini spec
--
-- 1: "1"
-- 2: "2"
-- 3: "fizz"
-- 4: "4"
-- 5: "buzz"
-- ...
--15: "fizzbuzz"


fizzbuzz :: Integer -> String
fizzbuzz x
    | (0 == x `mod` 3) && (0 == x `mod` 5) = "fizzbuzz"
    | 0 == x `mod` 3 = "fizz"
    | 0 == x `mod` 5 = "buzz"
    | otherwise = show x

add :: Integer -> Integer -> Integer
add x y = x + y

add4 :: Integer -> Integer
add4 = add 4

main = hspec $ do
    describe "Examples" $ do
        it "Backtick notation allows infix use of prefix functions" $ do
            shouldBe (mod 3 3) 0
            mod 3 3 `shouldBe` 0
            3 `mod` 3 `shouldBe` 0
        it "In Haskell, all functions really are curried, one-argument functions (!!)" $ do
            (add 4) 5 `shouldBe` 9
            add4 5 `shouldBe` 9

            let add3 = add 3
            add3 1 `shouldBe` 4

    describe "Regular numbers" $ do
        it "1 return '1'" $ do
            fizzbuzz 1 `shouldBe` "1"
        it "2 return '2'" $ do
            fizzbuzz 2 `shouldBe` "2"
        it "3 return 'fizz'" $ do
            fizzbuzz 3 `shouldBe` "fizz"
        it "5 return 'buzz'" $ do
            fizzbuzz 5 `shouldBe` "buzz"
        it "6 return 'fizz'" $ do
            fizzbuzz 6 `shouldBe` "fizz"

        it "15 return 'fizzbuzz'" $ do
            fizzbuzz 15 `shouldBe` "fizzbuzz"