Remove maybeDecompress_plain property

cabal-install/tests/UnitTests/Distribution/Client/GZipUtils.hs

@@ -20,11 +20,12 @@ import Test.Tasty.QuickCheck
 
 tests :: [TestTree]
 tests = [ testCase "maybeDecompress" maybeDecompressUnitTest
-        , testProperty "decompress plain" $ forAll (listOf asciiWord8) prop_maybeDecompress_plain
+        -- "decompress plain" property is non-trivial to state,
+        -- maybeDecompress returns input bytestring only if error occurs right at the beginning of the decompression process
+        -- generating such input would essentially duplicate maybeDecompress implementation
         , testProperty "decompress zlib"  prop_maybeDecompress_zlib
         , testProperty "decompress gzip"  prop_maybeDecompress_gzip
         ]
-  where asciiWord8 = elements [32..126]
 
 maybeDecompressUnitTest :: Assertion
 maybeDecompressUnitTest =
@@ -43,10 +44,6 @@ maybeDecompressUnitTest =
     runBrokenStream :: IO (Either SomeException ())
     runBrokenStream = try . void . evaluate . BSLL.length $ maybeDecompress (BSLL.init compressedZlib <> BSLL.pack "*")
 
-prop_maybeDecompress_plain :: [Word8] -> Property
-prop_maybeDecompress_plain ws = property $ maybeDecompress original === original
-  where original = BSL.pack ws
-
 prop_maybeDecompress_zlib :: [Word8] -> Property
 prop_maybeDecompress_zlib ws = property $ maybeDecompress compressedZlib === original
   where original = BSL.pack ws