Tests.QuickCheckUtils: clean-up

tests/Tests/QuickCheckUtils.hs

@@ -32,12 +32,12 @@ module Tests.QuickCheckUtils
 
 import Control.Arrow ((***))
 import Control.DeepSeq (NFData (..), deepseq)
-import Control.Exception (bracket)
 import Data.Char (isSpace)
 import Data.Coerce (coerce)
 import Data.Text.Foreign (I8)
 import Data.Text.Lazy.Builder.RealFloat (FPFormat(..))
 import Data.Word (Word8, Word16)
+import GHC.Num (integerLog2)
 import Test.QuickCheck hiding (Fixed(..), Small (..), (.&.))
 import Tests.Utils
 import qualified Data.ByteString as B
@@ -50,6 +50,7 @@ import qualified Data.Text.Internal.Lazy as TL
 import qualified Data.Text.Internal.Lazy.Fusion as TLF
 import qualified Data.Text.Lazy as TL
 import qualified System.IO as IO
+import Control.Applicative (liftA2, liftA3)
 
 genWord8 :: Gen Word8
 genWord8 = chooseAny
@@ -59,7 +60,7 @@ instance Arbitrary I8 where
     shrink        = shrinkIntegral
 
 instance Arbitrary B.ByteString where
-    arbitrary     = B.pack `fmap` listOf genWord8
+    arbitrary     = B.pack <$> listOf genWord8
     shrink        = map B.pack . shrink . B.unpack
 
 instance Arbitrary BL.ByteString where
@@ -69,10 +70,13 @@ instance Arbitrary BL.ByteString where
       , BL.fromChunks . map B.singleton <$> listOf genWord8
       -- so that a code point with 4 byte long utf8 representation
       -- could appear split over 3 non-singleton chunks
-      , (\a b c -> BL.fromChunks [a, b, c])
-        <$> arbitrary
-        <*> ((\a b -> B.pack [a, b]) <$> genWord8 <*> genWord8)
-        <*> arbitrary
+      , liftA3 (\a b c -> BL.fromChunks [a, b, c])
+          arbitrary
+          (liftA2 (\a b -> B.pack [a, b])
+            genWord8
+            genWord8
+          )
+          arbitrary
       ]
     shrink xs = BL.fromChunks <$> shrink (BL.toChunks xs)
 
@@ -84,7 +88,7 @@ newtype Sqrt a = Sqrt { unSqrt :: a }
 instance Arbitrary a => Arbitrary (Sqrt a) where
     arbitrary = coerce $ sized $ \n -> resize (smallish n) $ arbitrary @a
      where
-      smallish = round . (sqrt :: Double -> Double) . fromIntegral . abs
+      smallish = round . sqrt @Double . fromIntegral . abs
     shrink = coerce (shrink @a)
 
 instance Arbitrary T.Text where
@@ -136,12 +140,12 @@ data DecodeErr = Lenient | Ignore | Strict | Replace
  deriving (Show, Eq, Bounded, Enum)
 
 genDecodeErr :: DecodeErr -> Gen T.OnDecodeError
-genDecodeErr Lenient = return T.lenientDecode
-genDecodeErr Ignore  = return T.ignore
-genDecodeErr Strict  = return T.strictDecode
+genDecodeErr Lenient = pure T.lenientDecode
+genDecodeErr Ignore  = pure T.ignore
+genDecodeErr Strict  = pure T.strictDecode
 genDecodeErr Replace = (\c _ _ -> c) <$>
   frequency
-    [ (1, return Nothing)
+    [ (1, pure Nothing)
     , (50, pure <$> arbitraryUnicodeChar)
     ]
 
@@ -232,29 +236,31 @@ instance Arbitrary (Precision Double) where
     shrink    = coerce (shrink @(Maybe Int))
 
 instance Arbitrary IO.Newline where
-    arbitrary = oneof [return IO.LF, return IO.CRLF]
+    arbitrary = oneof [pure IO.LF, pure IO.CRLF]
 
 instance Arbitrary IO.NewlineMode where
     arbitrary = IO.NewlineMode <$> arbitrary <*> arbitrary
 
 instance Arbitrary IO.BufferMode where
-    arbitrary = oneof [ return IO.NoBuffering,
-                        return IO.LineBuffering,
-                        return (IO.BlockBuffering Nothing),
-                        (IO.BlockBuffering . Just . (+1) . fromIntegral) `fmap`
-                        (arbitrary :: Gen Word16) ]
+    arbitrary =
+      oneof
+        [ pure IO.NoBuffering
+        , pure IO.LineBuffering
+        , pure (IO.BlockBuffering Nothing)
+        , IO.BlockBuffering . pure . succ . fromIntegral <$> arbitrary @Word16
+        ]
 
 -- This test harness is complex!  What property are we checking?
 --
 -- Reading after writing a multi-line file should give the same
 -- results as were written.
 --
 -- What do we vary while checking this property?
--- * The lines themselves, scrubbed to contain neither CR nor LF.  (By
---   working with a list of lines, we ensure that the data will
---   sometimes contain line endings.)
--- * Newline translation mode.
--- * Buffering.
+--  * The lines themselves, scrubbed to contain neither CR nor LF.  (By
+--    working with a list of lines, we ensure that the data will
+--    sometimes contain line endings.)
+--  * Newline translation mode.
+--  * Buffering.
 write_read :: (NFData a, Eq a, Show a)
            => ([b] -> a)
            -> ((Char -> Bool) -> a -> b)
@@ -268,18 +274,18 @@ write_read _ _ _ _ (IO.NewlineMode IO.LF IO.CRLF) _ _ = discard
 write_read unline filt writer reader nl buf ts = ioProperty $
     (===t) <$> act
   where
-    t = unline . map (filt (not . (`elem` "\r\n"))) $ ts
+    t = unline . map (filt (`notElem` "\r\n")) $ ts
 
     act = withTempFile $ \path h -> do
             IO.hSetNewlineMode h nl
             IO.hSetBuffering h buf
             () <- writer h t
             IO.hClose h
-            bracket (IO.openFile path IO.ReadMode) IO.hClose $ \h' -> do
+            IO.withFile path IO.ReadMode $ \h' -> do
               IO.hSetNewlineMode h' nl
               IO.hSetBuffering h' buf
               r <- reader h'
-              r `deepseq` return r
+              r `deepseq` pure r
 
 -- Generate various Unicode space characters with high probability
 arbitrarySpacyChar :: Gen Char