module Test.Data.Ring where


import Test.QuickCheck (TestGroup(..), TestResult, quickCheck)
import Prelude hiding (filter)

abs :: Float -> Float
abs x = if x < 0.0 then 0.0-x else x + 0.0

absInt :: Int -> Int
absInt x = if x < 0 then -x else x

propSubInt :: Int->Bool
propSubInt x = (-x + x == 0)

propSubFloat :: Float->Bool
propSubFloat x = (-x + x - 0.0) < 0.0001

propDivFloat :: Float->Float->Bool
propDivFloat x y = if y == 0.0 then true else abs ((x/y) * y - x) < 0.0001

divIntTest :: Bool
divIntTest = (15 / 3 == 5) && (15 / 7 == 2) && (-15 / 7 == -2) && (-2 / 15 == 0)

test :: TestGroup (Integer -> IO TestResult)
test = Exe [ 
    quickCheck "propSubInt" propSubInt
   ,quickCheck "propSubFloat" propSubFloat
   ,quickCheck "propDivFloat" propDivFloat
   ,quickCheck "divIntTest" divIntTest
]