Haskell UTCTime Arbitrary instance

UTCTimeArbitrary.hs

import Data.Time

instance Arbitrary UTCTime where
    arbitrary =
        do randomDay <- choose (1, 29) :: Gen Int
           randomMonth <- choose (1, 12) :: Gen Int
           randomYear <- choose (2001, 2002) :: Gen Integer
           randomTime <- choose (0, 86401) :: Gen Int
           return $ UTCTime (fromGregorian randomYear randomMonth randomDay) (fromIntegral randomTime)

Yoink!