megaparsec/tests/Error.hs
mrkkrp 4c34c488cc Remove ‘Enum’ instance of ‘Message’
This was Parsec's legacy that we should eliminate now. ‘Message’ does
not constitute enumeration, ‘toEnum’ was never properly defined for
it. The idea to use ‘fromEnum’ to determine type of ‘Message’ is also
ugly, for this purpose new functions ‘isUnexpected’, ‘isExpected’, and
‘isMessage’ are defined in ‘Text.Megaparsec.Error’.
2016-02-18 16:26:29 +06:00

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--
-- QuickCheck tests for Megaparsec's parse errors.
--
-- Copyright © 20152016 Megaparsec contributors
--
-- Redistribution and use in source and binary forms, with or without
-- modification, are permitted provided that the following conditions are
-- met:
--
-- * Redistributions of source code must retain the above copyright notice,
-- this list of conditions and the following disclaimer.
--
-- * Redistributions in binary form must reproduce the above copyright
-- notice, this list of conditions and the following disclaimer in the
-- documentation and/or other materials provided with the distribution.
--
-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS “AS IS” AND ANY
-- EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-- WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-- DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
-- DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
-- DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
-- OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
-- HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
-- STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
-- ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-- POSSIBILITY OF SUCH DAMAGE.
{-# OPTIONS -fno-warn-orphans #-}
module Error (tests) where
import Data.Foldable (find)
import Data.List (isPrefixOf, isInfixOf)
import Data.Maybe (fromJust)
import Data.Monoid ((<>))
import Test.Framework
import Test.Framework.Providers.QuickCheck2 (testProperty)
import Test.QuickCheck
import Pos ()
import Text.Megaparsec.Error
import Text.Megaparsec.Pos
#if !MIN_VERSION_base(4,8,0)
import Control.Applicative ((<$>), (<*>))
import Data.Monoid (mempty)
#endif
tests :: Test
tests = testGroup "Parse errors"
[ testProperty "monoid left identity" prop_monoid_left_id
, testProperty "monoid right identity" prop_monoid_right_id
, testProperty "monoid associativity" prop_monoid_assoc
, testProperty "extraction of message string" prop_messageString
, testProperty "creation of new error messages" prop_newErrorMessage
, testProperty "messages are always well-formed" prop_wellFormedMessages
, testProperty "copying of error positions" prop_parseErrorCopy
, testProperty "setting of error position" prop_setErrorPos
, testProperty "addition of error message" prop_addErrorMessage
, testProperty "setting of error message" prop_setErrorMessage
, testProperty "position of merged error" prop_mergeErrorPos
, testProperty "messages of merged error" prop_mergeErrorMsgs
, testProperty "position of error is visible" prop_visiblePos
, testProperty "message components are visible" prop_visibleMsgs ]
instance Arbitrary Message where
arbitrary = ($) <$> elements constructors <*> arbitrary
where constructors = [Unexpected, Expected, Message]
instance Arbitrary ParseError where
arbitrary = do
ms <- listOf arbitrary
err <- oneof [ newErrorUnknown <$> arbitrary
, newErrorMessage <$> arbitrary <*> arbitrary ]
return $ addErrorMessages ms err
prop_monoid_left_id :: ParseError -> Bool
prop_monoid_left_id x = mempty <> x == x
prop_monoid_right_id :: ParseError -> Bool
prop_monoid_right_id x = x <> mempty == x
prop_monoid_assoc :: ParseError -> ParseError -> ParseError -> Bool
prop_monoid_assoc x y z = (x <> y) <> z == x <> (y <> z)
prop_messageString :: Message -> Bool
prop_messageString m@(Unexpected s) = s == messageString m
prop_messageString m@(Expected s) = s == messageString m
prop_messageString m@(Message s) = s == messageString m
prop_newErrorMessage :: Message -> SourcePos -> Bool
prop_newErrorMessage msg pos = added && errorPos new == pos
where new = newErrorMessage msg pos
added = errorMessages new == if badMessage msg then [] else [msg]
prop_wellFormedMessages :: ParseError -> Bool
prop_wellFormedMessages = wellFormed . errorMessages
prop_parseErrorCopy :: ParseError -> Bool
prop_parseErrorCopy err =
foldr addErrorMessage (newErrorUnknown pos) msgs == err
where pos = errorPos err
msgs = errorMessages err
prop_setErrorPos :: SourcePos -> ParseError -> Bool
prop_setErrorPos pos err =
errorPos new == pos && errorMessages new == errorMessages err
where new = setErrorPos pos err
prop_addErrorMessage :: Message -> ParseError -> Bool
prop_addErrorMessage msg err =
wellFormed msgs && (badMessage msg || added)
where new = addErrorMessage msg err
msgs = errorMessages new
added = msg `elem` msgs && not (errorIsUnknown new)
prop_setErrorMessage :: Message -> ParseError -> Bool
prop_setErrorMessage msg err =
wellFormed msgs && (badMessage msg || (added && unique))
where new = setErrorMessage msg err
msgs = errorMessages new
added = msg `elem` msgs && not (errorIsUnknown new)
unique = length (filter f msgs) == 1
f = fromJust $ find ($ msg) [isUnexpected, isExpected, isMessage]
prop_mergeErrorPos :: ParseError -> ParseError -> Bool
prop_mergeErrorPos e1 e2 = errorPos (mergeError e1 e2) == max pos1 pos2
where pos1 = errorPos e1
pos2 = errorPos e2
prop_mergeErrorMsgs :: ParseError -> ParseError -> Bool
prop_mergeErrorMsgs e1 e2' = errorPos e1 /= errorPos e2 || wellFormed msgsm
where e2 = setErrorPos (errorPos e1) e2'
msgsm = errorMessages $ mergeError e1 e2
prop_visiblePos :: ParseError -> Bool
prop_visiblePos err = show (errorPos err) `isPrefixOf` show err
prop_visibleMsgs :: ParseError -> Bool
prop_visibleMsgs err = if null msgs
then "unknown" `isInfixOf` shown
else all (`isInfixOf` shown) (msgs >>= f)
where shown = show err
msgs = errorMessages err
f (Unexpected s) = ["unexpected", s]
f (Expected s) = ["expecting", s]
f (Message s) = [s]
-- | @wellFormed xs@ checks that list @xs@ is sorted and contains no
-- duplicates and no empty messages.
wellFormed :: [Message] -> Bool
wellFormed xs = and (zipWith (<) xs (tail xs)) && not (any badMessage xs)