module ErrorTest where

import ErrorPath
import Test.HUnit hiding (Path)
import SimpleExpr

main :: IO ()
main = runTestTT tests >> return ()

tests :: Test
tests = test
  [ assertOkay 6 $ calc (2 + 4)
  , assertFailWith [0] $ calc (1 + 4)
  , assertFailWith [0] $ calc (5 + 5)
  , assertFailWith [1] $ calc (2 + 5)
  , assertFailWith [1] $ calc ((2 + 2) + 3)
  , assertFailWith [1,1] $ calc (2 + (2 + 3))
  , assertFailWith [0,1] $ calc ((2 + 3) + 3)
  ]

calc :: Expr -> ErrorPath String Int
calc = foldExprE evalAlg

assertFailWith :: Path -> ErrorPath e a -> Assertion
assertFailWith p ep = case runErrorPath ep of
  Left (_, p')  -> assertEqual "" p p'
  _             -> assertFailure "expected failure but found success"

assertOkay :: (Eq a, Show a) => a -> ErrorPath e a -> Assertion
assertOkay v ep = case runErrorPath ep of
  Right v'  -> assertEqual "" v v'
  _         -> assertFailure "expected success but found failure"