Haxl/tests/CoreTests.hs

{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE PatternGuards #-}
{-# LANGUAGE RebindableSyntax #-}
module CoreTests where

import Haxl.Prelude
import Prelude ()

import Haxl.Core

import Test.HUnit

import Data.Aeson
import qualified Data.ByteString.Lazy.Char8 as BS

import Control.Exception (Exception(..))

useless :: String -> GenHaxl u Bool
useless _ = throw (NotFound "ha ha")

en = error "no env"

exceptions :: Assertion
exceptions =
  do
    a <- runHaxl en $ try (useless "input")
    assertBool "NotFound -> HaxlException" $
      isLeft (a :: Either HaxlException Bool)

    b <- runHaxl en $ try (useless "input")
    assertBool "NotFound -> Logic Error" $
      isLeft (b :: Either LogicError Bool)

    c <- runHaxl en $ try (useless "input")
    assertBool "NotFound -> NotFound" $
      isLeft (c :: Either NotFound Bool)

    -- Make sure TransientError -doesn't- catch our NotFound
    d <- runHaxl en $
             (useless "input"
              `catch` \TransientError{} -> return False)
             `catch` \LogicError{} -> return True
    assertBool "Transient != NotFound" d

    -- test catch
    e <- runHaxl en $
         throw (NotFound "haha") `catch` \NotFound{} -> return True
    assertBool "catch1" e

    f <- runHaxl en $
         throw (NotFound "haha") `catch` \LogicError{} -> return True
    assertBool "catch2" f

    -- test catchIf
    let transientOrNotFound e
          | Just TransientError{} <- fromException e  = True
          | Just NotFound{} <- fromException e  = True
          | otherwise = False

    e <- runHaxl en $
         catchIf transientOrNotFound (throw (NotFound "haha")) $ \_ ->
           return True
    assertBool "catchIf1" e

    e <- runHaxl en $
         catchIf transientOrNotFound (throw (FetchError "haha")) $ \_ ->
           return True
    assertBool "catchIf2" e

    e <- runHaxl en $
           (catchIf transientOrNotFound (throw (CriticalError "haha")) $ \_ ->
              return True)
            `catch` \InternalError{} -> return False
    assertBool "catchIf2" (not e)
  where
  isLeft Left{} = True
  isLeft _ = False


-- This is mostly a compile test, to make sure all the plumbing
-- makes the compiler happy.
base :: (Exception a) => a -> IO HaxlException
base e = runHaxl en $ throw e `catch` \x -> return x

printing :: Assertion
printing = do
  a <- base $ NotFound "notfound!"
  print a

  b <- base $ CriticalError "ohthehumanity!"
  print b

  c <- base $ FetchError "timeout!"
  print c

  BS.putStrLn $ encode a
  BS.putStrLn $ encode b
  BS.putStrLn $ encode c


tests = TestList
  [ TestLabel "exceptions" $ TestCase exceptions,
    TestLabel "print_stuff" $ TestCase printing
  ]