Created
June 21, 2019 11:25
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Unit Interval QuickCheck [0,1]
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| import qualified Data.Fixed as FP | |
| import Test.QuickCheck | |
| data E34 | |
| instance FP.HasResolution E34 where | |
| resolution _ = 10^34 | |
| type FixedPoint = FP.Fixed E34 | |
| newtype UnitInterval a = Unit a deriving Show | |
| instance (Fractional a, Arbitrary a) => Arbitrary (UnitInterval a) where | |
| arbitrary = return . Unit . toUnit =<< arbitrary | |
| type NonNegInts = (NonNegative Integer, Positive Integer) | |
| normalizeInts :: NonNegInts -> (Integer,Integer) | |
| normalizeInts (NonNegative x, Positive y) = (min x y, max x y) | |
| normalize :: Fractional a => NonNegInts -> (a,a) | |
| normalize = mapp fromInteger . normalizeInts | |
| where mapp f (x,y) = (f x, f y) | |
| toUnit :: Fractional a => NonNegInts -> a | |
| toUnit = uncurry (/) . normalize -- [0,1] | |
| prop_Unit :: UnitInterval FixedPoint -> Property | |
| prop_Unit (Unit x) = classify (x==1) "= 1" $ | |
| classify (x==0) "= 0" $ | |
| (0 <= x && x <= 1) === True | |
| main = quickCheck (withMaxSuccess 100000 prop_Unit) |
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Testing QuickCheck Arbitrary instance of Unit Interval [0,1] with Fixed Point arithmetic.