Multicheck.hs

{-|
Module:      Test.Hspec.Multicheck
Description: A testing framework based on hspec.
Copyright:   (c) Marcellus Siegburg, 2017
License:     PublicDomain
Maintainer:  Marcellus Siegburg <msi@informatik.uni-kiel.de>
Stability:   Experimental

This module imports and reexports Hspec.
However, the functions 'it' and 'specify' are changed.
Thus, QuickCheck and smallcheck are executed for every test case that is
specified using this library.
-}
{-# OPTIONS_GHC -fno-warn-orphans #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE FlexibleContexts #-}
module Test.Hspec.Multicheck (
  module Test.Hspec,
  (==>), it, property, specify
  ) where

import qualified Test.QuickCheck       as QC
import qualified Test.SmallCheck       as SC
import qualified Test.Hspec.SmallCheck as SC
import           Test.Hspec            hiding (it, specify)
import qualified Test.Hspec            as Hspec

import Prelude hiding (length)

{-|
Creates a spec item for SmallCheck and QuickCheck by calling Hspecs 'Hspec.it' for each
within the spec monad.
-}
it :: (QC.Testable prop, SC.Testable IO prop) => String -> prop -> Spec
it descr p = do
  Hspec.it (descr ++ " (SC)") $ SC.property p
  Hspec.it (descr ++ " (QC)") $ QC.property p

{-|
A synonym for 'it'.
-}
specify :: (QC.Testable prop, SC.Testable IO prop) => String -> prop -> Spec
specify = it

infixr 0 ==>

{-|
Implication for properties: Applied using Smallchecks 'SC.==>' and
QuickChecks 'QC.==>' and returned as tuple.
-}
(==>) :: (SC.Testable m prop, QC.Testable prop)
  => Bool -> prop -> (SC.Property m, QC.Property)
cond ==> p = (cond SC.==> p, cond QC.==> p)

{-|
Converts the given parameter to a tuple of properties.
I.e. a Smallcheck 'SC.Property' and a QuickCheck 'QC.Property'.
-}
property :: (SC.Testable IO prop, QC.Testable prop)
  => prop -> (SC.Property IO, QC.Property)
property p = (SC.property p, QC.property p)

instance QC.Testable (SC.Property m, QC.Property) where
  property (_, p) = QC.property p

instance (Monad m, m ~ n) => SC.Testable n (SC.Property m, QC.Property) where
  test (p, _) = SC.test p