module Darcs.Test.Util.TestResult
  ( TestResult
  , succeeded
  , failed
  , rejected
  , (<&&>)
  , fromMaybe
  , isOk
  , isFailed
  ) where

import Darcs.Util.Printer (Doc, renderString)

import qualified Test.QuickCheck.Property as Q

data TestResult
  = TestSucceeded
  | TestFailed Doc
  | TestRejected

succeeded :: TestResult
succeeded = TestSucceeded

failed :: Doc -> TestResult
failed = TestFailed

rejected :: TestResult
rejected = TestRejected

-- | Succeed even if one of the arguments is rejected.
(<&&>) :: TestResult -> TestResult -> TestResult
t@(TestFailed _) <&&> _s = t
_t <&&> s@(TestFailed _) = s
TestRejected <&&> s = s
t <&&> TestRejected = t
TestSucceeded <&&> TestSucceeded = TestSucceeded

-- | 'Nothing' is considered success whilst 'Just' is considered failure.
fromMaybe :: Maybe Doc -> TestResult
fromMaybe Nothing = succeeded
fromMaybe (Just errMsg) = failed errMsg

isFailed :: TestResult -> Bool
isFailed (TestFailed _) = True
isFailed _other = False

-- | A test is considered Ok if it does not fail.
isOk :: TestResult -> Bool
isOk = not . isFailed

-- | 'Testable' instance is defined by converting 'TestResult' to
-- 'QuickCheck.Property.Result'
instance Q.Testable TestResult where
  property TestSucceeded = Q.property Q.succeeded
  property (TestFailed errorMsg) =
    Q.property (Q.failed {Q.reason = renderString errorMsg})
  property TestRejected = Q.property Q.rejected