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{- | Tests for the Data.Prefix.Units module

-}

module Main (main) where

import Data.Char (toUpper)
import Data.List
import Test.Framework (Test, defaultMain, testGroup)
import Test.Framework.Providers.QuickCheck2 (testProperty)
import Test.QuickCheck

import Data.Prefix.Units

-- * Test helpers

failTest :: String -> Property
failTest msg = printTestCase msg False

-- | Checks for equality with proper annotation.
(==?) :: (Show a, Eq a) => a -> a -> Property
(==?) x y = printTestCase
            ("Expected equality, but '" ++
             show x ++ "' /= '" ++ show y ++ "'") (x == y)
infix 3 ==?

-- | Formats a failed-to-parse-unit message.
failParseUnit :: Unit -> String -> Property
failParseUnit unit err =
  failTest $ "Failed to parse unit '" ++ unitName unit ++ "': " ++ err

-- | Fails unless we received an error message that passes a given
-- condition.
expectParseFailure :: (Show a) =>
                      (String -> Bool)
                   -> Either String a
                   -> Property
expectParseFailure fn (Left err) =
  printTestCase "Unexpected error message" $ fn err
expectParseFailure _  (Right v)  =
  failTest $ "Unexpected parse with result " ++ show v

-- | Expect a parse result to be a given value.
expectParse :: (Real a, Real b) => a -> Unit -> Either String b -> Property
expectParse _ unit (Left err) = failParseUnit unit err
expectParse v unit (Right v') =
  printTestCase "Parsed wrong value: " $
  toRational v' ==? toRational v * unitMultiplier unit

-- * Instances

instance Arbitrary Unit where
  arbitrary = elements [minBound..maxBound]

instance Arbitrary FormatMode where
  arbitrary = elements [minBound..maxBound]

instance Arbitrary ParseMode where
  arbitrary = elements [minBound..maxBound]

allUnits :: [Unit]
allUnits = [minBound..maxBound]

-- * Actual tests

-- ** Definitions

testUniqueNames :: Property
testUniqueNames =
  let names = map unitName allUnits
  in names ==? nub names

testUniqueSymbols :: Property
testUniqueSymbols =
  let symbols = map unitSymbol allUnits
  in symbols ==? nub symbols

testUniqueFancySymbols :: Property
testUniqueFancySymbols =
  let symbols = map fancySymbol allUnits
  in symbols ==? nub symbols

testOrdering :: Property
testOrdering =
  let si_mult = map unitMultiplier $ sort siUnits
      bin_mult = map unitMultiplier $ sort binaryUnits
      all_mult = map unitMultiplier allUnits -- no sorting here!
  in si_mult ==? sort si_mult .&&.
     bin_mult ==? sort bin_mult .&&.
     all_mult ==? sort all_mult

testSIBinary :: Property
testSIBinary =
  printTestCase "SI unit lists contain binary prefixes" $
                (null (siUnits `intersect` binaryUnits)) .&&.
                (null (siKMGT `intersect` binaryUnits)) .&&.
                (null (siSupraunitary `intersect` binaryUnits))

-- ** Parsing

testNullUnitInt :: Int -> ParseMode -> Property
testNullUnitInt v pmode =
  case parseValue pmode (show v) of
    Left err -> failTest $ "Failed to parse empty unit: " ++ err
    Right v' -> printTestCase "Parsed wrong value:" (v ==? v')

testNullUnitFrac :: Double -> ParseMode -> Property
testNullUnitFrac d pmode =
  case parseValue pmode (show d) of
    Left err -> failTest $ "Failed to parse empty unit: " ++ err
    Right d' -> printTestCase "Parsed wrong value:" (d ==? d')

testSymbolParsingExact :: Unit -> Property
testSymbolParsingExact unit =
  case parseExactSymbol (unitSymbol unit) of
    Left err -> failParseUnit unit err
    Right unit' -> printTestCase "Parsed wrong unit: " (unit ==? unit')

-- | Binary units should parse themselves in explicit binary mode.
testSymbolParsingBinary :: Property
testSymbolParsingBinary =
  forAll (elements binaryUnits) $ \unit ->
  case parseBinarySymbol (unitSymbol unit) of
    Left err -> failParseUnit unit err
    Right unit' -> printTestCase "Parsed wrong unit: " (unit ==? unit')

-- | Binary units should parse themselves in all parsing modes.
testSymbolParsingBinaryAbbrev :: Property
testSymbolParsingBinaryAbbrev =
  forAll (elements binaryUnits) $ \unit ->
  case parseSymbol ParseBinary (take 1 (unitSymbol unit)) of
    Left err -> failParseUnit unit err
    Right unit' -> printTestCase "Parsed wrong unit: " (unit ==? unit')

-- | Binary units should parse themselves in all parsing modes.
testSymbolParsingBinaryAll :: ParseMode -> Property
testSymbolParsingBinaryAll mode =
  forAll (elements binaryUnits) $ \unit ->
  case parseSymbol mode (unitSymbol unit) of
    Left err -> failParseUnit unit err
    Right unit' -> printTestCase "Parsed wrong unit: " (unit ==? unit')

-- | Fail to parse invalid symbols in any mode.
testSymbolParsingFail :: ParseMode -> Property
testSymbolParsingFail mode =
  expectParseFailure (("NO-SUCH" `isInfixOf`) . map toUpper) $
    parseSymbol mode ("no-such")

-- | Parsed values should be correct.
testParsingIntKMGT :: Int -> Property
testParsingIntKMGT v =
  forAll (elements (siKMGT ++ binaryUnits)) $ \unit ->
  let str = show v ++ unitSymbol unit in
  expectParse v unit (parseValue ParseKMGT str::Either String Integer)

-- | Parsed values should be correct.
testParsingInt :: Int -> Property
testParsingInt v =
  forAll (elements (siSupraunitary ++ binaryUnits)) $ \unit ->
  let str = show v ++ unitSymbol unit in
  expectParse v unit (parseValue ParseExact str::Either String Integer)

-- | Parsed values should be correct.
--
-- Note that this tests floating point number equality, so it could be
-- flaky.
testParsingDouble :: Unit -> Double -> Property
testParsingDouble unit d =
  let str = show d ++ unitSymbol unit in
  case (parseValue ParseExact str)::Either String Double of
    Left err -> failParseUnit unit err
    Right d' -> printTestCase ("Parsing of " ++ str ++ " failed: ") $
                d' ==? fromRational (toRational d * unitMultiplier unit)

-- | Parsed values should be correct.
testParsingRational :: Unit -> Integer -> Property
testParsingRational unit v =
  let str = show v ++ "%1" ++ unitSymbol unit in
  expectParse v unit (parseValue ParseExact str::Either String Rational)

testFailParsing :: ParseMode -> Int -> Property
testFailParsing pmode v =
  expectParseFailure ("no-such" `isInfixOf`)
    (parseValue pmode ("no-such" ++ show v)::Either String Int)

-- | Test fail parse on required unit.
testParsingRequired :: ParseMode -> Int -> Property
testParsingRequired pmode v =
  expectParseFailure ("is required" `isInfixOf`)
    (parseGeneric UnitRequired [] pmode (show v)::Either String Int)

testParsingDefault :: Unit -> ParseMode -> Rational -> Property
testParsingDefault unit pmode v =
  expectParse v unit
    (parseGeneric (UnitDefault unit) [] pmode (show v)::Either String Rational)

testParsingInvalidList :: Unit -> [Unit] -> Int -> Property
testParsingInvalidList unit valid v =
  unit `notElem` valid && not (null valid) ==>
  expectParseFailure ("not part of the accepted unit list" `isInfixOf`)
    (parseGeneric UnitOptional valid ParseExact
       (show v ++ unitSymbol unit)::Either String Int)

testParsingValidList :: Unit -> [Unit] -> Rational -> Property
testParsingValidList unit valid v =
  unit `elem` valid && not (null valid) ==>
  expectParse v unit
   (parseGeneric UnitOptional valid ParseExact
      (show v ++ unitSymbol unit)::Either String Rational)

-- ** Formatting

testTrivialFormattingRec :: FormatMode -> Property
testTrivialFormattingRec fmt =
  recommendedUnit fmt (0::Int) ==? Nothing .&&.
  recommendedUnit fmt (0::Double) ==? Nothing

testTrivialFormattingFmt :: FormatMode -> Property
testTrivialFormattingFmt fmt =
  formatValue (Left fmt) (0::Int) ==? (0, Nothing) .&&.
  formatValue (Left fmt) (0::Double) ==? (0, Nothing)

testTrivialFormattingShow :: FormatMode -> Property
testTrivialFormattingShow fmt =
  showValue (Left fmt) (0::Int) ==? "0" .&&.
  showValue (Left fmt) (0::Double) ==? show (0::Double)

testRecommend :: Property
testRecommend =
  forAll (elements [FormatSiAll, FormatBinary]) $ \fmt ->
  forAll (elements (unitRange fmt)) $ \unit ->
  case recommendedUnit fmt (unitMultiplier unit) of
    Nothing -> failTest $ "Expected recommendation of unit " ++
               unitName unit ++ " but got nothing"
    Just unit' -> printTestCase "Mismatch in recommended unit: " $
                  unit ==? unit'

testForceUnit :: Unit -> Rational -> Property
testForceUnit unit v =
  case formatValue (Right unit) v of
    (v', Just u') -> printTestCase "Invalid value/unit computed" $
                     unit ==? u' .&&.
                     v ==? v' * unitMultiplier unit
    x -> failTest $ "Invalid result from formatValue: " ++ show x

testFormatIntegral :: Property
testFormatIntegral =
  forAll (elements [FormatSiSupraunitary, FormatBinary]) $ \fmt ->
  forAll (elements (unitRange fmt)) $ \unit ->
  let fmted = formatValue (Left fmt) . truncate . unitMultiplier $ unit
  in fmted ==? (1::Integer, Just unit)

testFormatFractional :: Property
testFormatFractional =
  forAll (elements [FormatSiSupraunitary, FormatBinary]) $ \fmt ->
  forAll (elements (unitRange fmt)) $ \unit ->
  let fmted = formatValue (Left fmt) . unitMultiplier $ unit
  in fmted ==? (1::Rational, Just unit)

testShowIntegralBinary :: Property
testShowIntegralBinary =
  forAll (elements binaryUnits) $ \ unit ->
  let value = truncate (unitMultiplier unit)::Integer in
  printTestCase ("Formatting/showing unit " ++ show unit) $
   showValue (Left FormatBinary) value ==? "1" ++ unitSymbol unit

testShowRational :: Unit -> Property
testShowRational unit =
  let fmtmode = if unit `elem` binaryUnits then FormatBinary else FormatSiAll
      value = unitMultiplier unit
  in printTestCase ("Formatting/showing unit " ++ show unit) $
     showValue (Left fmtmode) value ==? "1 % 1" ++ unitSymbol unit

-- * Test harness

main :: IO ()
main = defaultMain tests

tests :: [Test]
tests =
  [ testGroup "definitions"
    [ testProperty "unique names" testUniqueNames
    , testProperty "unique symbols" testUniqueSymbols
    , testProperty "unique fancy symbols" testUniqueFancySymbols
    , testProperty "ordering" testOrdering
    , testProperty "type mixup" testSIBinary
    ]
  , testGroup "parsing"
    [ testProperty "null unit integral" testNullUnitInt
    , testProperty "null unit fractional" testNullUnitFrac
    , testProperty "symbol parsing/exact" testSymbolParsingExact
    , testProperty "symbol parsing/binary" testSymbolParsingBinary
    , testProperty "symbol parsing/binary-all" testSymbolParsingBinaryAll
    , testProperty "symbol parsing/binary-abbrev" testSymbolParsingBinaryAbbrev
    , testProperty "symbol parsing/failure" testSymbolParsingFail
    , testProperty "parsing/integral-kmgt" testParsingIntKMGT
    , testProperty "parsing/integral" testParsingInt
    , testProperty "parsing/fractional" testParsingDouble
    , testProperty "parsing/rational" testParsingRational
    , testProperty "parsing/failure" testFailParsing
    , testProperty "parsing/required unit" testParsingRequired
    , testProperty "parsing/default" testParsingDefault
    , testProperty "parsing/invalid-list" testParsingInvalidList
    , testProperty "parsing/valid-list" testParsingValidList
    ]
  , testGroup "formatting"
    [ testProperty "trivial formatting/recommend" testTrivialFormattingRec
    , testProperty "trivial formatting/fmt" testTrivialFormattingFmt
    , testProperty "trivial formatting/show" testTrivialFormattingShow
    , testProperty "recommend" testRecommend
    , testProperty "force unit" testForceUnit
    , testProperty "format/int" testFormatIntegral
    , testProperty "format/frac" testFormatFractional
    , testProperty "show/integral binary" testShowIntegralBinary
    , testProperty "show/rational" testShowRational
    ]
  ]