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{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}
module Snap.Test.Common
( coverEqInstance
, coverOrdInstance
, coverReadInstance
, coverShowInstance
, coverTypeableInstance
, forceSameType
, expectException
, expectExceptionH
, liftQ
, eatException
, waitabit
, seconds
) where
------------------------------------------------------------------------------
import Control.Concurrent (threadDelay)
import Control.DeepSeq (deepseq)
import Control.Exception.Lifted (SomeException (..), catch, evaluate, try)
import Control.Monad (Monad ((>>), return), liftM, replicateM)
import Control.Monad.IO.Class (MonadIO (..))
import Control.Monad.Trans.Control (MonadBaseControl)
import qualified Data.ByteString as S
import Data.ByteString.Internal (c2w)
import qualified Data.ByteString.Lazy as L
import Data.Typeable (Typeable, typeOf)
import Prelude (Either (..), Eq (..), IO, Int, Num (..), Ord (..), Ordering (..), Read (..), Show (..), fail, map, seq, ($), (.), (^))
import Test.QuickCheck (Arbitrary (arbitrary), choose)
import Test.QuickCheck.Monadic (PropertyM)
import qualified Test.QuickCheck.Monadic as QC
------------------------------------------------------------------------------
------------------------------------------------------------------------------
instance Arbitrary S.ByteString where
arbitrary = liftM (S.pack . map c2w) arbitrary
instance Arbitrary L.ByteString where
arbitrary = do
n <- choose(0,5)
chunks <- replicateM n arbitrary
return $ L.fromChunks chunks
------------------------------------------------------------------------------
eatException :: (MonadBaseControl IO m) => m a -> m ()
eatException a = (a >> return ()) `catch` handler
where
handler :: (MonadBaseControl IO m) => SomeException -> m ()
handler _ = return ()
------------------------------------------------------------------------------
forceSameType :: a -> a -> a
forceSameType _ a = a
------------------------------------------------------------------------------
-- | Kill the false negative on derived show instances.
coverShowInstance :: (Monad m, Show a) => a -> m ()
coverShowInstance x = a `deepseq` b `deepseq` c `deepseq` return ()
where
a = showsPrec 0 x ""
b = show x
c = showList [x] ""
------------------------------------------------------------------------------
coverReadInstance :: (MonadIO m, Read a) => a -> m ()
coverReadInstance x = do
liftIO $ eatException $ evaluate $ forceSameType [(x,"")] $ readsPrec 0 ""
liftIO $ eatException $ evaluate $ forceSameType [([x],"")] $ readList ""
------------------------------------------------------------------------------
coverEqInstance :: (Monad m, Eq a) => a -> m ()
coverEqInstance x = a `seq` b `seq` return ()
where
a = x == x
b = x /= x
------------------------------------------------------------------------------
coverOrdInstance :: (Monad m, Ord a) => a -> m ()
coverOrdInstance x = a `deepseq` b `deepseq` return ()
where
a = [ x < x
, x >= x
, x > x
, x <= x
, compare x x == EQ ]
b = min a $ max a a
------------------------------------------------------------------------------
coverTypeableInstance :: (Monad m, Typeable a) => a -> m ()
coverTypeableInstance a = typeOf a `seq` return ()
------------------------------------------------------------------------------
expectException :: IO a -> PropertyM IO ()
expectException m = do
e <- liftQ $ try m
case e of
Left (z::SomeException) -> (forceList $ show z) `seq` return ()
Right _ -> fail "expected exception, didn't get one"
------------------------------------------------------------------------------
expectExceptionH :: IO a -> IO ()
expectExceptionH act = do
e <- try act
case e of
Left (z::SomeException) -> (forceList $ show z) `seq` return ()
Right _ -> fail "expected exception, didn't get one"
------------------------------------------------------------------------------
forceList :: [a] -> ()
forceList [] = ()
forceList (x:xs) = x `seq` forceList xs
------------------------------------------------------------------------------
liftQ :: forall a m . (Monad m) => m a -> PropertyM m a
liftQ = QC.run
------------------------------------------------------------------------------
waitabit :: IO ()
waitabit = threadDelay $ 2*seconds
------------------------------------------------------------------------------
seconds :: Int
seconds = (10::Int) ^ (6::Int)
|
