fizz_buzz_kata_2016_pbt.hs

newtype Fizz = Fizz Int deriving (Show)
newtype Buzz = Buzz Int deriving (Show)
newtype Other = Other Int deriving (Show)

instance Arbitrary Fizz where
  arbitrary = do
    x <- (arbitrary `suchThat` (\n -> fizzBuzz n == "Fizz"))
    return (Fizz x)

instance Arbitrary Buzz where
  arbitrary = do
    x <- (arbitrary `suchThat` (\n -> fizzBuzz n == "Buzz"))
    return (Buzz x)

instance Arbitrary Other where
  arbitrary = do
    x <- (arbitrary `suchThat` (\n -> fizzBuzz n == (show n) && n /= 0))
    return (Other x)

prop_fizzBuzz :: Fizz -> Buzz -> Bool
prop_fizzBuzz (Fizz a) (Buzz b) = fizzBuzz (a * b) == "FizzBuzz"

prop_fizzFizz :: Fizz -> Fizz -> Bool
prop_fizzFizz (Fizz a) (Fizz b) = fizzBuzz (a * b) == "Fizz"

prop_buzzBuzz :: Buzz -> Buzz -> Bool
prop_buzzBuzz (Buzz a) (Buzz b) = fizzBuzz (a * b) == "Buzz"

prop_fizz :: Other -> Fizz -> Bool
prop_fizz (Other a) (Fizz b) = fizzBuzz (a * b) == "Fizz"

prop_buzz :: Other -> Buzz -> Bool
prop_buzz (Other a) (Buzz b) = fizzBuzz (a * b) == "Buzz"