{-# LANGUAGE CPP #-}
{-
	Copyright (C) 2012 Dr. Alistair Ward

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program.  If not, see <http://www.gnu.org/licenses/>.
-}
{- |
 [@AUTHOR@]	Dr. Alistair Ward

 [@DESCRIPTION@]	Defines /QuickCheck/-properties "ToolShed.Data.List.Splits".
-}

module ToolShed.Test.Data.List.Splits(
-- * Functions
	quickChecks
) where

import			Control.Arrow((***))
import qualified	Data.List
import qualified	Data.Ord
import qualified	Data.Set
import qualified	ToolShed.Data.List.Splits
import qualified	Test.QuickCheck
import			Test.QuickCheck((==>))

#if MIN_VERSION_base(4,3,0)
import	Data.Tuple(swap)
#else
-- | Swap the components of a pair.
swap :: (a, b) -> (b, a)
swap (a, b)	= (b, a)
#endif

-- | Defines invariant properties.
quickChecks :: IO ()
quickChecks	= Test.QuickCheck.quickCheck prop_splitsFrom where
	prop_splitsFrom :: Int -> [Int] -> Test.QuickCheck.Property
	prop_splitsFrom i l	= not (null l) ==> Test.QuickCheck.label "prop_splitsFrom" $ take n (ToolShed.Data.List.Splits.splitsLeftFrom index l) == take n (map (swap . (reverse *** reverse)) . ToolShed.Data.List.Splits.splitsRightFrom (length l - index) $ reverse l)	where
		index	= i `mod` length l
		n	= succ index