{-# LANGUAGE QuasiQuotes #-}

module Data.Cfg.ReachableTests
  ( tests
  ) where

import Data.Cfg.Bnf (bnf)
import Data.Cfg.Cfg (Cfg(..), V(..))
import Data.Cfg.FreeCfg (FreeCfg(..), toFreeCfg)
import Data.Cfg.Reachable
import Data.Cfg.TestGrammars (assertEqCfg, wiki)
import qualified Data.Set as S
import Test.Framework (Test, testGroup)
import Test.Framework.Providers.HUnit (testCase)
import Test.HUnit (assertEqual)
import Text.PrettyPrint

tests :: Test
tests = testGroup "Data.Cfg.Reachable" [wikiTest]

wikiTest :: Test
wikiTest =
  testCase "wiki reachability test" $ do
    assertEqual "reachables" (S.fromList $ words "s b c e") (reachables wiki)
    assertEqual "unreachables" (S.fromList $ words "d") (unreachables wiki)
    assertEqCfg ctxt ctxt "reachability" expected $ removeUnreachables wiki
  where
    ctxt :: V String String -> Doc
    ctxt v =
      text $
      case v of
        NT nt -> nt
        T t -> t
    reach =
      [bnf|
    s ::= b B | c C | e E.
    b ::= b B | B.
    c ::= c C | C.
    e ::= e E.
    |]
    expected :: FreeCfg String String
    expected = (toFreeCfg reach) {terminals' = terminals wiki}