Coding Dojo Haskell 001

Fibonacci.hs

module Fibonacci where

fibonacci 1 = 0
fibonacci 2 = 1
fibonacci n = fibonacci(n - 1) + fibonacci(n - 2)

Makefile

test:
	@runhaskell Test.hs

dependencies:
	cabal update
	cabal install hspec base-unicode-symbols

Test.hs

import Test.Hspec

import Fibonacci

-- Fibonacci
-- 1 -> 0
-- 2 -> 1
-- 3 -> 1
-- 4 -> 2
-- 5 -> 3
-- 6 -> 5

main = hspec $ do
    describe "Fibonacci numbers" $ do
        it "1 => 0" $ do
            fibonacci 1 `shouldBe` 0
        it "2 => 1" $ do
            fibonacci 2 `shouldBe` 1
        it "3 => 1" $ do
            fibonacci 3 `shouldBe` 1
        it "4 => 2" $ do
            fibonacci 4 `shouldBe` 2

    describe "Fibonacci undefined arguments" $ do
        it "should fail for 0" $ do
            fibonacci 0 `shouldThrow` anyException