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|
{- QuickCheck with additional instances
-
- Copyright 2012-2020 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
{-# OPTIONS_GHC -fno-warn-orphans #-}
{-# OPTIONS_GHC -fno-warn-tabs #-}
{-# LANGUAGE TypeSynonymInstances #-}
module Utility.QuickCheck
( module X
, TestableString
, fromTestableString
, TestableFilePath(..)
, nonNegative
, positive
) where
import Test.QuickCheck as X
import Data.Time.Clock.POSIX
import Data.Ratio
import Data.Char
import System.Posix.Types
import Data.List.NonEmpty (NonEmpty(..))
import Prelude
{- A String, but Arbitrary is limited to ascii.
-
- When in a non-utf8 locale, String does not normally contain any non-ascii
- characters, except for ones in surrogate plane. Converting a string that
- does contain other unicode characters to a ByteString using the
- filesystem encoding (see GHC.IO.Encoding) will throw an exception,
- so use this instead to avoid quickcheck tests breaking unncessarily.
-}
newtype TestableString = TestableString
{ fromTestableString :: String }
deriving (Show)
instance Arbitrary TestableString where
arbitrary = TestableString . filter isAscii <$> arbitrary
{- FilePath constrained to not be the empty string, not contain a NUL,
- and contain only ascii.
-
- No real-world filename can be empty or contain a NUL. So code can
- well be written that assumes that and using this avoids quickcheck
- tests breaking unncessarily.
-}
newtype TestableFilePath = TestableFilePath
{ fromTestableFilePath :: FilePath }
deriving (Show)
instance Arbitrary TestableFilePath where
arbitrary = (TestableFilePath . fromTestableString <$> arbitrary)
`suchThat` (not . null . fromTestableFilePath)
`suchThat` (not . any (== '\NUL') . fromTestableFilePath)
{- 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
instance Arbitrary l => Arbitrary (NonEmpty l) where
arbitrary = (:|) <$> arbitrary <*> arbitrary
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)
|
