QC.hs

{-
	Copyright (C) 2010 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 tests to dynamically verify the module "Squeeze.Squeeze" against arbitrary data.
-}

module Squeeze.Test.QC(
-- * Types
-- ** Type-synonyms
--	Testable,
-- * Functions
	quickChecks
) where

import qualified	Control.Arrow
import qualified	Data.List
import qualified	Factory.Data.Interval
import qualified	Squeeze.Data.File		as Data.File
import qualified	Squeeze.Data.FileCombination	as Data.FileCombination
import qualified	Squeeze.Squeeze			as Squeeze
import qualified	Test.QuickCheck
import			Test.QuickCheck((==>))

type Testable	= [Data.File.FileSizeAndPath] -> Test.QuickCheck.Property

-- | Defines invariant properties, which must hold for any 'FileSizeAndPath'.
quickChecks :: (Testable -> IO ()) -> IO ()
quickChecks	= (`mapM_` [prop_bisectionRatio, prop_totalCombinations, prop_bounds, prop_all])	where
	translate :: [Data.File.FileSizeAndPath] -> [Data.File.FileSizeAndPath]
	translate	= Data.List.nub . map (Control.Arrow.first abs)

	prop_bisectionRatio, prop_totalCombinations, prop_bounds, prop_all :: Testable
	prop_bisectionRatio fileSizeAndPathList	= not (null l)	==> Test.QuickCheck.label "prop_bisectionRatio" $ (== 1) . length . Data.List.nub . map (
		\bisectionRatio	-> Data.List.sort . Squeeze.distribute bisectionRatio fileSizeBounds $ Data.File.orderBySize l
	 ) . take (length l) $ map recip [1 :: Double ..]	where
		l :: [Data.File.FileSizeAndPath]
		l	= take 14 {-arbitrarily-} $ translate fileSizeAndPathList	--CAVEAT: may be shorter than requested.

		fileSizeBounds :: Factory.Data.Interval.Interval Data.File.FileSize
		fileSizeBounds	= (minimumBytes, maximumBytes)	where
			maximumBytes, minimumBytes :: Data.File.FileSize
			maximumBytes	= round $ fromIntegral (Data.File.aggregateSize l) / (4.0 :: Double)	--Arbitrarily.
			minimumBytes	= maximumBytes `div` 2	--Arbitrarily.

	prop_totalCombinations fileSizeAndPathList	=  Test.QuickCheck.label "prop_totalCombinations" $ (length . Data.List.nub . Squeeze.findCombinations (0, fromIntegral (maxBound :: Int)) $ Data.File.orderBySize l) == 2 ^ length l where
		l :: [Data.File.FileSizeAndPath]
		l	= take 10 {-arbitrarily-} $ translate fileSizeAndPathList	--CAVEAT: may be shorter than requested.

	prop_bounds fileSizeAndPathList	=  Test.QuickCheck.label "prop_bounds" . all ((`Factory.Data.Interval.elem'` fileSizeBounds) . Data.FileCombination.getAggregateFileSize) . Squeeze.findCombinations fileSizeBounds $ Data.File.orderBySize l	where
		l :: [Data.File.FileSizeAndPath]
		l	= take 16 {-arbitrarily-} $ translate fileSizeAndPathList	--CAVEAT: may be shorter than requested.

		fileSizeBounds :: Factory.Data.Interval.Interval Data.File.FileSize
		fileSizeBounds	= (minimumBytes, maximumBytes)	where
			maximumBytes, minimumBytes :: Data.File.FileSize
			maximumBytes	= round $ fromIntegral (Data.File.aggregateSize l) / (4.0 :: Double)	--Arbitrarily.
			minimumBytes	= maximumBytes `div` 2	--Arbitrarily.

	prop_all fileSizeAndPathList =	Test.QuickCheck.label "prop_all" . (== bytes) . last . map Data.FileCombination.getAggregateFileSize $ Squeeze.findBestFit (recip 2 :: Double) (Factory.Data.Interval.precisely bytes) l	where
		l :: [Data.File.FileSizeAndPath]
		l	= take 16 {-arbitrarily-} $ translate fileSizeAndPathList	--CAVEAT: may be shorter than requested.

		bytes :: Data.File.FileSize
		bytes	= Data.File.aggregateSize l