git-annex/Utility/QuickCheck.hs
Joey Hess 2b52dbe905
fix build with older QuickCheck
The NonEmpty instance was moved out of QuickCheck and into a package
with more deps than I want to drag in, so I'm providing my own instance,
but with older QuickCheck, use theirs to avoid overlapping.
2019-03-22 10:07:16 -04:00

56 lines
1.5 KiB
Haskell

{- QuickCheck with additional instances
-
- Copyright 2012-2014 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
{-# LANGUAGE CPP #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}
{-# LANGUAGE TypeSynonymInstances #-}
module Utility.QuickCheck
( module X
, module Utility.QuickCheck
) where
import Test.QuickCheck as X
import Data.Time.Clock.POSIX
import Data.Ratio
import System.Posix.Types
import Data.List.NonEmpty (NonEmpty(..))
import Prelude
{- Times before the epoch are excluded. Half with decimal and half without. -}
instance Arbitrary POSIXTime where
arbitrary = do
n <- nonNegative arbitrarySizedBoundedIntegral :: Gen Int
d <- nonNegative arbitrarySizedIntegral
withd <- arbitrary
return $ if withd
then fromIntegral n + fromRational (1 % max d 1)
else fromIntegral n
{- Pids are never negative, or 0. -}
instance Arbitrary ProcessID where
arbitrary = positive arbitrarySizedBoundedIntegral
{- Inodes are never negative. -}
instance Arbitrary FileID where
arbitrary = nonNegative arbitrarySizedIntegral
{- File sizes are never negative. -}
instance Arbitrary FileOffset where
arbitrary = nonNegative arbitrarySizedIntegral
{- Latest Quickcheck lacks this instance. -}
#if MIN_VERSION_QuickCheck(2,10,0)
instance Arbitrary l => Arbitrary (NonEmpty l) where
arbitrary = (:|) <$> arbitrary <*> arbitrary
#endif
nonNegative :: (Num a, Ord a) => Gen a -> Gen a
nonNegative g = g `suchThat` (>= 0)
positive :: (Num a, Ord a) => Gen a -> Gen a
positive g = g `suchThat` (> 0)