-- | Type classes for random generation of values.
--
-- __Note__: the contents of this module are re-exported by
-- "Test.QuickCheck". You do not need to import it directly.
{-# LANGUAGE CPP #-}
{-# LANGUAGE FlexibleContexts #-}
#ifndef NO_GENERICS
{-# LANGUAGE DefaultSignatures, FlexibleContexts, TypeOperators #-}
{-# LANGUAGE FlexibleInstances, KindSignatures, ScopedTypeVariables #-}
{-# LANGUAGE MultiParamTypeClasses #-}
#if __GLASGOW_HASKELL__ >= 710
#define OVERLAPPING_ {-# OVERLAPPING #-}
#else
{-# LANGUAGE OverlappingInstances #-}
#define OVERLAPPING_
#endif
#endif
#ifndef NO_POLYKINDS
{-# LANGUAGE PolyKinds #-}
#endif
#ifndef NO_SAFE_HASKELL
{-# LANGUAGE Trustworthy #-}
#endif
#ifndef NO_NEWTYPE_DERIVING
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
#endif
module Test.QuickCheck.Arbitrary
(
-- * Arbitrary and CoArbitrary classes
Arbitrary(..)
, CoArbitrary(..)
-- ** Unary and Binary classes
, Arbitrary1(..)
, arbitrary1
, shrink1
, Arbitrary2(..)
, arbitrary2
, shrink2
-- ** Helper functions for implementing arbitrary
, applyArbitrary2
, applyArbitrary3
, applyArbitrary4
, arbitrarySizedIntegral -- :: Integral a => Gen a
, arbitrarySizedNatural -- :: Integral a => Gen a
, arbitraryBoundedIntegral -- :: (Bounded a, Integral a) => Gen a
, arbitrarySizedBoundedIntegral -- :: (Bounded a, Integral a) => Gen a
, arbitrarySizedFractional -- :: Fractional a => Gen a
, arbitraryBoundedRandom -- :: (Bounded a, Random a) => Gen a
, arbitraryBoundedEnum -- :: (Bounded a, Enum a) => Gen a
-- ** Generators for various kinds of character
, arbitraryUnicodeChar -- :: Gen Char
, arbitraryASCIIChar -- :: Gen Char
, arbitraryPrintableChar -- :: Gen Char
-- ** Helper functions for implementing shrink
#ifndef NO_GENERICS
, genericShrink -- :: (Generic a, Arbitrary a, RecursivelyShrink (Rep a), GSubterms (Rep a) a) => a -> [a]
, subterms -- :: (Generic a, Arbitrary a, GSubterms (Rep a) a) => a -> [a]
, recursivelyShrink -- :: (Generic a, RecursivelyShrink (Rep a)) => a -> [a]
, genericCoarbitrary -- :: (Generic a, GCoArbitrary (Rep a)) => a -> Gen b -> Gen b
#endif
, shrinkNothing -- :: a -> [a]
, shrinkList -- :: (a -> [a]) -> [a] -> [[a]]
, shrinkMap -- :: Arbitrary a -> (a -> b) -> (b -> a) -> b -> [b]
, shrinkMapBy -- :: (a -> b) -> (b -> a) -> (a -> [a]) -> b -> [b]
, shrinkIntegral -- :: Integral a => a -> [a]
, shrinkRealFrac -- :: RealFrac a => a -> [a]
, shrinkDecimal -- :: RealFrac a => a -> [a]
-- ** Helper functions for implementing coarbitrary
, coarbitraryIntegral -- :: Integral a => a -> Gen b -> Gen b
, coarbitraryReal -- :: Real a => a -> Gen b -> Gen b
, coarbitraryShow -- :: Show a => a -> Gen b -> Gen b
, coarbitraryEnum -- :: Enum a => a -> Gen b -> Gen b
, (><)
-- ** Generators which use arbitrary
, vector -- :: Arbitrary a => Int -> Gen [a]
, orderedList -- :: (Ord a, Arbitrary a) => Gen [a]
, infiniteList -- :: Arbitrary a => Gen [a]
)
where
--------------------------------------------------------------------------
-- imports
import Control.Applicative
import Data.Foldable(toList)
import System.Random(Random)
import Test.QuickCheck.Gen
import Test.QuickCheck.Random
import Test.QuickCheck.Gen.Unsafe
{-
import Data.Generics
( (:*:)(..)
, (:+:)(..)
, Unit(..)
)
-}
import Data.Char
( ord
, isLower
, isUpper
, toLower
, isDigit
, isSpace
, isPrint
, generalCategory
, GeneralCategory(..)
)
#ifndef NO_FIXED
import Data.Fixed
( Fixed
, HasResolution
)
#endif
import Data.Ratio
( Ratio
, (%)
, numerator
, denominator
)
import Data.Complex
( Complex((:+)) )
import Data.List
( sort
, nub
)
import Data.Version (Version (..))
import Control.Monad
( liftM
, liftM2
, liftM3
, liftM4
, liftM5
)
import Data.Int(Int8, Int16, Int32, Int64)
import Data.Word(Word, Word8, Word16, Word32, Word64)
import System.Exit (ExitCode(..))
import Foreign.C.Types
#ifndef NO_GENERICS
import GHC.Generics
#endif
import qualified Data.Set as Set
import qualified Data.Map as Map
import qualified Data.IntSet as IntSet
import qualified Data.IntMap as IntMap
import qualified Data.Sequence as Sequence
import qualified Data.Monoid as Monoid
#ifndef NO_TRANSFORMERS
import Data.Functor.Identity
import Data.Functor.Constant
import Data.Functor.Compose
import Data.Functor.Product
#endif
--------------------------------------------------------------------------
-- ** class Arbitrary
-- | Random generation and shrinking of values.
--
-- QuickCheck provides @Arbitrary@ instances for most types in @base@,
-- except those which incur extra dependencies.
-- For a wider range of @Arbitrary@ instances see the
--
-- package.
class Arbitrary a where
-- | A generator for values of the given type.
--
-- It is worth spending time thinking about what sort of test data
-- you want - good generators are often the difference between
-- finding bugs and not finding them. You can use 'sample',
-- 'label' and 'classify' to check the quality of your test data.
--
-- There is no generic @arbitrary@ implementation included because we don't
-- know how to make a high-quality one. If you want one, consider using the
-- or
-- packages.
--
-- The
-- goes into detail on how to write good generators. Make sure to look at it,
-- especially if your type is recursive!
arbitrary :: Gen a
-- | Produces a (possibly) empty list of all the possible
-- immediate shrinks of the given value.
--
-- The default implementation returns the empty list, so will not try to
-- shrink the value. If your data type has no special invariants, you can
-- enable shrinking by defining @shrink = 'genericShrink'@, but by customising
-- the behaviour of @shrink@ you can often get simpler counterexamples.
--
-- Most implementations of 'shrink' should try at least three things:
--
-- 1. Shrink a term to any of its immediate subterms.
-- You can use 'subterms' to do this.
--
-- 2. Recursively apply 'shrink' to all immediate subterms.
-- You can use 'recursivelyShrink' to do this.
--
-- 3. Type-specific shrinkings such as replacing a constructor by a
-- simpler constructor.
--
-- For example, suppose we have the following implementation of binary trees:
--
-- > data Tree a = Nil | Branch a (Tree a) (Tree a)
--
-- We can then define 'shrink' as follows:
--
-- > shrink Nil = []
-- > shrink (Branch x l r) =
-- > -- shrink Branch to Nil
-- > [Nil] ++
-- > -- shrink to subterms
-- > [l, r] ++
-- > -- recursively shrink subterms
-- > [Branch x' l' r' | (x', l', r') <- shrink (x, l, r)]
--
-- There are a couple of subtleties here:
--
-- * QuickCheck tries the shrinking candidates in the order they
-- appear in the list, so we put more aggressive shrinking steps
-- (such as replacing the whole tree by @Nil@) before smaller
-- ones (such as recursively shrinking the subtrees).
--
-- * It is tempting to write the last line as
-- @[Branch x' l' r' | x' <- shrink x, l' <- shrink l, r' <- shrink r]@
-- but this is the /wrong thing/! It will force QuickCheck to shrink
-- @x@, @l@ and @r@ in tandem, and shrinking will stop once /one/ of
-- the three is fully shrunk.
--
-- There is a fair bit of boilerplate in the code above.
-- We can avoid it with the help of some generic functions.
-- The function 'genericShrink' tries shrinking a term to all of its
-- subterms and, failing that, recursively shrinks the subterms.
-- Using it, we can define 'shrink' as:
--
-- > shrink x = shrinkToNil x ++ genericShrink x
-- > where
-- > shrinkToNil Nil = []
-- > shrinkToNil (Branch _ l r) = [Nil]
--
-- 'genericShrink' is a combination of 'subterms', which shrinks
-- a term to any of its subterms, and 'recursivelyShrink', which shrinks
-- all subterms of a term. These may be useful if you need a bit more
-- control over shrinking than 'genericShrink' gives you.
--
-- A final gotcha: we cannot define 'shrink' as simply @'shrink' x = Nil:'genericShrink' x@
-- as this shrinks @Nil@ to @Nil@, and shrinking will go into an
-- infinite loop.
--
-- If all this leaves you bewildered, you might try @'shrink' = 'genericShrink'@ to begin with,
-- after deriving @Generic@ for your type. However, if your data type has any
-- special invariants, you will need to check that 'genericShrink' can't break those invariants.
shrink :: a -> [a]
shrink _ = []
-- | Lifting of the 'Arbitrary' class to unary type constructors.
class Arbitrary1 f where
liftArbitrary :: Gen a -> Gen (f a)
liftShrink :: (a -> [a]) -> f a -> [f a]
liftShrink _ _ = []
arbitrary1 :: (Arbitrary1 f, Arbitrary a) => Gen (f a)
arbitrary1 = liftArbitrary arbitrary
shrink1 :: (Arbitrary1 f, Arbitrary a) => f a -> [f a]
shrink1 = liftShrink shrink
-- | Lifting of the 'Arbitrary' class to binary type constructors.
class Arbitrary2 f where
liftArbitrary2 :: Gen a -> Gen b -> Gen (f a b)
liftShrink2 :: (a -> [a]) -> (b -> [b]) -> f a b -> [f a b]
liftShrink2 _ _ _ = []
arbitrary2 :: (Arbitrary2 f, Arbitrary a, Arbitrary b) => Gen (f a b)
arbitrary2 = liftArbitrary2 arbitrary arbitrary
shrink2 :: (Arbitrary2 f, Arbitrary a, Arbitrary b) => f a b -> [f a b]
shrink2 = liftShrink2 shrink shrink
#ifndef NO_GENERICS
-- | Shrink a term to any of its immediate subterms,
-- and also recursively shrink all subterms.
genericShrink :: (Generic a, RecursivelyShrink (Rep a), GSubterms (Rep a) a) => a -> [a]
genericShrink x = subterms x ++ recursivelyShrink x
-- | Recursively shrink all immediate subterms.
recursivelyShrink :: (Generic a, RecursivelyShrink (Rep a)) => a -> [a]
recursivelyShrink = map to . grecursivelyShrink . from
class RecursivelyShrink f where
grecursivelyShrink :: f a -> [f a]
instance (RecursivelyShrink f, RecursivelyShrink g) => RecursivelyShrink (f :*: g) where
grecursivelyShrink (x :*: y) =
[x' :*: y | x' <- grecursivelyShrink x] ++
[x :*: y' | y' <- grecursivelyShrink y]
instance (RecursivelyShrink f, RecursivelyShrink g) => RecursivelyShrink (f :+: g) where
grecursivelyShrink (L1 x) = map L1 (grecursivelyShrink x)
grecursivelyShrink (R1 x) = map R1 (grecursivelyShrink x)
instance RecursivelyShrink f => RecursivelyShrink (M1 i c f) where
grecursivelyShrink (M1 x) = map M1 (grecursivelyShrink x)
instance Arbitrary a => RecursivelyShrink (K1 i a) where
grecursivelyShrink (K1 x) = map K1 (shrink x)
instance RecursivelyShrink U1 where
grecursivelyShrink U1 = []
instance RecursivelyShrink V1 where
-- The empty type can't be shrunk to anything.
grecursivelyShrink _ = []
-- | All immediate subterms of a term.
subterms :: (Generic a, GSubterms (Rep a) a) => a -> [a]
subterms = gSubterms . from
class GSubterms f a where
-- | Provides the immediate subterms of a term that are of the same type
-- as the term itself.
--
-- Requires a constructor to be stripped off; this means it skips through
-- @M1@ wrappers and returns @[]@ on everything that's not `(:*:)` or `(:+:)`.
--
-- Once a `(:*:)` or `(:+:)` constructor has been reached, this function
-- delegates to `gSubtermsIncl` to return the immediately next constructor
-- available.
gSubterms :: f a -> [a]
instance GSubterms V1 a where
-- The empty type can't be shrunk to anything.
gSubterms _ = []
instance GSubterms U1 a where
gSubterms U1 = []
instance (GSubtermsIncl f a, GSubtermsIncl g a) => GSubterms (f :*: g) a where
gSubterms (l :*: r) = gSubtermsIncl l ++ gSubtermsIncl r
instance (GSubtermsIncl f a, GSubtermsIncl g a) => GSubterms (f :+: g) a where
gSubterms (L1 x) = gSubtermsIncl x
gSubterms (R1 x) = gSubtermsIncl x
instance GSubterms f a => GSubterms (M1 i c f) a where
gSubterms (M1 x) = gSubterms x
instance GSubterms (K1 i a) b where
gSubterms (K1 _) = []
class GSubtermsIncl f a where
-- | Provides the immediate subterms of a term that are of the same type
-- as the term itself.
--
-- In contrast to `gSubterms`, this returns the immediate next constructor
-- available.
gSubtermsIncl :: f a -> [a]
instance GSubtermsIncl V1 a where
-- The empty type can't be shrunk to anything.
gSubtermsIncl _ = []
instance GSubtermsIncl U1 a where
gSubtermsIncl U1 = []
instance (GSubtermsIncl f a, GSubtermsIncl g a) => GSubtermsIncl (f :*: g) a where
gSubtermsIncl (l :*: r) = gSubtermsIncl l ++ gSubtermsIncl r
instance (GSubtermsIncl f a, GSubtermsIncl g a) => GSubtermsIncl (f :+: g) a where
gSubtermsIncl (L1 x) = gSubtermsIncl x
gSubtermsIncl (R1 x) = gSubtermsIncl x
instance GSubtermsIncl f a => GSubtermsIncl (M1 i c f) a where
gSubtermsIncl (M1 x) = gSubtermsIncl x
-- This is the important case: We've found a term of the same type.
instance OVERLAPPING_ GSubtermsIncl (K1 i a) a where
gSubtermsIncl (K1 x) = [x]
instance OVERLAPPING_ GSubtermsIncl (K1 i a) b where
gSubtermsIncl (K1 _) = []
#endif
-- instances
instance (CoArbitrary a) => Arbitrary1 ((->) a) where
liftArbitrary arbB = promote (`coarbitrary` arbB)
instance (CoArbitrary a, Arbitrary b) => Arbitrary (a -> b) where
arbitrary = arbitrary1
instance Arbitrary () where
arbitrary = return ()
instance Arbitrary Bool where
arbitrary = choose (False,True)
shrink True = [False]
shrink False = []
instance Arbitrary Ordering where
arbitrary = elements [LT, EQ, GT]
shrink GT = [EQ, LT]
shrink LT = [EQ]
shrink EQ = []
instance Arbitrary1 Maybe where
liftArbitrary arb = frequency [(1, return Nothing), (3, liftM Just arb)]
liftShrink shr (Just x) = Nothing : [ Just x' | x' <- shr x ]
liftShrink _ Nothing = []
instance Arbitrary a => Arbitrary (Maybe a) where
arbitrary = arbitrary1
shrink = shrink1
instance Arbitrary2 Either where
liftArbitrary2 arbA arbB = oneof [liftM Left arbA, liftM Right arbB]
liftShrink2 shrA _ (Left x) = [ Left x' | x' <- shrA x ]
liftShrink2 _ shrB (Right y) = [ Right y' | y' <- shrB y ]
instance Arbitrary a => Arbitrary1 (Either a) where
liftArbitrary = liftArbitrary2 arbitrary
liftShrink = liftShrink2 shrink
instance (Arbitrary a, Arbitrary b) => Arbitrary (Either a b) where
arbitrary = arbitrary2
shrink = shrink2
instance Arbitrary1 [] where
liftArbitrary = listOf
liftShrink = shrinkList
instance Arbitrary a => Arbitrary [a] where
arbitrary = arbitrary1
shrink = shrink1
-- | Shrink a list of values given a shrinking function for individual values.
shrinkList :: (a -> [a]) -> [a] -> [[a]]
shrinkList shr xs = concat [ removes k n xs | k <- takeWhile (>0) (iterate (`div`2) n) ]
++ shrinkOne xs
where
n = length xs
shrinkOne [] = []
shrinkOne (x:xs) = [ x':xs | x' <- shr x ]
++ [ x:xs' | xs' <- shrinkOne xs ]
removes k n xs
| k > n = []
| null xs2 = [[]]
| otherwise = xs2 : map (xs1 ++) (removes k (n-k) xs2)
where
xs1 = take k xs
xs2 = drop k xs
{-
-- "standard" definition for lists:
shrink [] = []
shrink (x:xs) = [ xs ]
++ [ x:xs' | xs' <- shrink xs ]
++ [ x':xs | x' <- shrink x ]
-}
instance Integral a => Arbitrary (Ratio a) where
arbitrary = arbitrarySizedFractional
shrink = shrinkRealFrac
instance (RealFloat a, Arbitrary a) => Arbitrary (Complex a) where
arbitrary = liftM2 (:+) arbitrary arbitrary
shrink (x :+ y) = [ x' :+ y | x' <- shrink x ] ++
[ x :+ y' | y' <- shrink y ]
#ifndef NO_FIXED
instance HasResolution a => Arbitrary (Fixed a) where
arbitrary = arbitrarySizedFractional
shrink = shrinkDecimal
#endif
instance Arbitrary2 (,) where
liftArbitrary2 = liftM2 (,)
liftShrink2 shrA shrB (x, y) =
[ (x', y) | x' <- shrA x ]
++ [ (x, y') | y' <- shrB y ]
instance (Arbitrary a) => Arbitrary1 ((,) a) where
liftArbitrary = liftArbitrary2 arbitrary
liftShrink = liftShrink2 shrink
instance (Arbitrary a, Arbitrary b) => Arbitrary (a,b) where
arbitrary = arbitrary2
shrink = shrink2
instance (Arbitrary a, Arbitrary b, Arbitrary c)
=> Arbitrary (a,b,c)
where
arbitrary = liftM3 (,,) arbitrary arbitrary arbitrary
shrink (x, y, z) =
[ (x', y', z')
| (x', (y', z')) <- shrink (x, (y, z)) ]
instance (Arbitrary a, Arbitrary b, Arbitrary c, Arbitrary d)
=> Arbitrary (a,b,c,d)
where
arbitrary = liftM4 (,,,) arbitrary arbitrary arbitrary arbitrary
shrink (w, x, y, z) =
[ (w', x', y', z')
| (w', (x', (y', z'))) <- shrink (w, (x, (y, z))) ]
instance (Arbitrary a, Arbitrary b, Arbitrary c, Arbitrary d, Arbitrary e)
=> Arbitrary (a,b,c,d,e)
where
arbitrary = liftM5 (,,,,) arbitrary arbitrary arbitrary arbitrary arbitrary
shrink (v, w, x, y, z) =
[ (v', w', x', y', z')
| (v', (w', (x', (y', z')))) <- shrink (v, (w, (x, (y, z)))) ]
instance ( Arbitrary a, Arbitrary b, Arbitrary c, Arbitrary d, Arbitrary e
, Arbitrary f
)
=> Arbitrary (a,b,c,d,e,f)
where
arbitrary = return (,,,,,)
<*> arbitrary <*> arbitrary <*> arbitrary <*> arbitrary
<*> arbitrary <*> arbitrary
shrink (u, v, w, x, y, z) =
[ (u', v', w', x', y', z')
| (u', (v', (w', (x', (y', z'))))) <- shrink (u, (v, (w, (x, (y, z))))) ]
instance ( Arbitrary a, Arbitrary b, Arbitrary c, Arbitrary d, Arbitrary e
, Arbitrary f, Arbitrary g
)
=> Arbitrary (a,b,c,d,e,f,g)
where
arbitrary = return (,,,,,,)
<*> arbitrary <*> arbitrary <*> arbitrary <*> arbitrary
<*> arbitrary <*> arbitrary <*> arbitrary
shrink (t, u, v, w, x, y, z) =
[ (t', u', v', w', x', y', z')
| (t', (u', (v', (w', (x', (y', z')))))) <- shrink (t, (u, (v, (w, (x, (y, z)))))) ]
instance ( Arbitrary a, Arbitrary b, Arbitrary c, Arbitrary d, Arbitrary e
, Arbitrary f, Arbitrary g, Arbitrary h
)
=> Arbitrary (a,b,c,d,e,f,g,h)
where
arbitrary = return (,,,,,,,)
<*> arbitrary <*> arbitrary <*> arbitrary <*> arbitrary
<*> arbitrary <*> arbitrary <*> arbitrary <*> arbitrary
shrink (s, t, u, v, w, x, y, z) =
[ (s', t', u', v', w', x', y', z')
| (s', (t', (u', (v', (w', (x', (y', z')))))))
<- shrink (s, (t, (u, (v, (w, (x, (y, z))))))) ]
instance ( Arbitrary a, Arbitrary b, Arbitrary c, Arbitrary d, Arbitrary e
, Arbitrary f, Arbitrary g, Arbitrary h, Arbitrary i
)
=> Arbitrary (a,b,c,d,e,f,g,h,i)
where
arbitrary = return (,,,,,,,,)
<*> arbitrary <*> arbitrary <*> arbitrary <*> arbitrary
<*> arbitrary <*> arbitrary <*> arbitrary <*> arbitrary
<*> arbitrary
shrink (r, s, t, u, v, w, x, y, z) =
[ (r', s', t', u', v', w', x', y', z')
| (r', (s', (t', (u', (v', (w', (x', (y', z'))))))))
<- shrink (r, (s, (t, (u, (v, (w, (x, (y, z)))))))) ]
instance ( Arbitrary a, Arbitrary b, Arbitrary c, Arbitrary d, Arbitrary e
, Arbitrary f, Arbitrary g, Arbitrary h, Arbitrary i, Arbitrary j
)
=> Arbitrary (a,b,c,d,e,f,g,h,i,j)
where
arbitrary = return (,,,,,,,,,)
<*> arbitrary <*> arbitrary <*> arbitrary <*> arbitrary
<*> arbitrary <*> arbitrary <*> arbitrary <*> arbitrary
<*> arbitrary <*> arbitrary
shrink (q, r, s, t, u, v, w, x, y, z) =
[ (q', r', s', t', u', v', w', x', y', z')
| (q', (r', (s', (t', (u', (v', (w', (x', (y', z')))))))))
<- shrink (q, (r, (s, (t, (u, (v, (w, (x, (y, z))))))))) ]
-- typical instance for primitive (numerical) types
instance Arbitrary Integer where
arbitrary = arbitrarySizedIntegral
shrink = shrinkIntegral
instance Arbitrary Int where
arbitrary = arbitrarySizedIntegral
shrink = shrinkIntegral
instance Arbitrary Int8 where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary Int16 where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary Int32 where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary Int64 where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary Word where
arbitrary = arbitrarySizedIntegral
shrink = shrinkIntegral
instance Arbitrary Word8 where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary Word16 where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary Word32 where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary Word64 where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary Char where
arbitrary =
frequency
[(3, arbitraryASCIIChar),
(1, arbitraryUnicodeChar)]
shrink c = filter (<. c) $ nub
$ ['a','b','c']
++ [ toLower c | isUpper c ]
++ ['A','B','C']
++ ['1','2','3']
++ [' ','\n']
where
a <. b = stamp a < stamp b
stamp a = ( (not (isLower a)
, not (isUpper a)
, not (isDigit a))
, (not (a==' ')
, not (isSpace a)
, a)
)
instance Arbitrary Float where
arbitrary = arbitrarySizedFractional
shrink = shrinkDecimal
instance Arbitrary Double where
arbitrary = arbitrarySizedFractional
shrink = shrinkDecimal
instance Arbitrary CChar where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary CSChar where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary CUChar where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary CShort where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary CUShort where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary CInt where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary CUInt where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary CLong where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary CULong where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary CPtrdiff where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary CSize where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary CWchar where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary CSigAtomic where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary CLLong where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary CULLong where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary CIntPtr where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary CUIntPtr where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary CIntMax where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
instance Arbitrary CUIntMax where
arbitrary = arbitrarySizedBoundedIntegral
shrink = shrinkIntegral
#ifndef NO_CTYPES_CONSTRUCTORS
-- The following four types have no Bounded instance,
-- so we fake it by discovering the bounds at runtime.
instance Arbitrary CClock where
arbitrary = fmap CClock arbitrary
shrink (CClock x) = map CClock (shrink x)
instance Arbitrary CTime where
arbitrary = fmap CTime arbitrary
shrink (CTime x) = map CTime (shrink x)
#ifndef NO_FOREIGN_C_USECONDS
instance Arbitrary CUSeconds where
arbitrary = fmap CUSeconds arbitrary
shrink (CUSeconds x) = map CUSeconds (shrink x)
instance Arbitrary CSUSeconds where
arbitrary = fmap CSUSeconds arbitrary
shrink (CSUSeconds x) = map CSUSeconds (shrink x)
#endif
#endif
instance Arbitrary CFloat where
arbitrary = arbitrarySizedFractional
shrink = shrinkDecimal
instance Arbitrary CDouble where
arbitrary = arbitrarySizedFractional
shrink = shrinkDecimal
-- Arbitrary instances for container types
instance (Ord a, Arbitrary a) => Arbitrary (Set.Set a) where
arbitrary = fmap Set.fromList arbitrary
shrink = map Set.fromList . shrink . Set.toList
instance (Ord k, Arbitrary k) => Arbitrary1 (Map.Map k) where
liftArbitrary = fmap Map.fromList . liftArbitrary . liftArbitrary
liftShrink shr = map Map.fromList . liftShrink (liftShrink shr) . Map.toList
instance (Ord k, Arbitrary k, Arbitrary v) => Arbitrary (Map.Map k v) where
arbitrary = arbitrary1
shrink = shrink1
instance Arbitrary IntSet.IntSet where
arbitrary = fmap IntSet.fromList arbitrary
shrink = map IntSet.fromList . shrink . IntSet.toList
instance Arbitrary1 IntMap.IntMap where
liftArbitrary = fmap IntMap.fromList . liftArbitrary . liftArbitrary
liftShrink shr = map IntMap.fromList . liftShrink (liftShrink shr) . IntMap.toList
instance Arbitrary a => Arbitrary (IntMap.IntMap a) where
arbitrary = arbitrary1
shrink = shrink1
instance Arbitrary1 Sequence.Seq where
liftArbitrary = fmap Sequence.fromList . liftArbitrary
liftShrink shr = map Sequence.fromList . liftShrink shr . toList
instance Arbitrary a => Arbitrary (Sequence.Seq a) where
arbitrary = arbitrary1
shrink = shrink1
-- Arbitrary instance for Ziplist
instance Arbitrary1 ZipList where
liftArbitrary = fmap ZipList . liftArbitrary
liftShrink shr = map ZipList . liftShrink shr . getZipList
instance Arbitrary a => Arbitrary (ZipList a) where
arbitrary = arbitrary1
shrink = shrink1
#ifndef NO_TRANSFORMERS
-- Arbitrary instance for transformers' Functors
instance Arbitrary1 Identity where
liftArbitrary = fmap Identity
liftShrink shr = map Identity . shr . runIdentity
instance Arbitrary a => Arbitrary (Identity a) where
arbitrary = arbitrary1
shrink = shrink1
instance Arbitrary2 Constant where
liftArbitrary2 arbA _ = fmap Constant arbA
liftShrink2 shrA _ = fmap Constant . shrA . getConstant
instance Arbitrary a => Arbitrary1 (Constant a) where
liftArbitrary = liftArbitrary2 arbitrary
liftShrink = liftShrink2 shrink
-- Have to be defined explicitly, as Constant is kind polymorphic
instance Arbitrary a => Arbitrary (Constant a b) where
arbitrary = fmap Constant arbitrary
shrink = map Constant . shrink . getConstant
instance (Arbitrary1 f, Arbitrary1 g) => Arbitrary1 (Product f g) where
liftArbitrary arb = liftM2 Pair (liftArbitrary arb) (liftArbitrary arb)
liftShrink shr (Pair f g) =
[ Pair f' g | f' <- liftShrink shr f ] ++
[ Pair f g' | g' <- liftShrink shr g ]
instance (Arbitrary1 f, Arbitrary1 g, Arbitrary a) => Arbitrary (Product f g a) where
arbitrary = arbitrary1
shrink = shrink1
instance (Arbitrary1 f, Arbitrary1 g) => Arbitrary1 (Compose f g) where
liftArbitrary = fmap Compose . liftArbitrary . liftArbitrary
liftShrink shr = map Compose . liftShrink (liftShrink shr) . getCompose
instance (Arbitrary1 f, Arbitrary1 g, Arbitrary a) => Arbitrary (Compose f g a) where
arbitrary = arbitrary1
shrink = shrink1
#endif
-- Arbitrary instance for Const
instance Arbitrary2 Const where
liftArbitrary2 arbA _ = fmap Const arbA
liftShrink2 shrA _ = fmap Const . shrA . getConst
instance Arbitrary a => Arbitrary1 (Const a) where
liftArbitrary = liftArbitrary2 arbitrary
liftShrink = liftShrink2 shrink
-- Have to be defined explicitly, as Const is kind polymorphic
instance Arbitrary a => Arbitrary (Const a b) where
arbitrary = fmap Const arbitrary
shrink = map Const . shrink . getConst
instance Arbitrary (m a) => Arbitrary (WrappedMonad m a) where
arbitrary = WrapMonad <$> arbitrary
shrink (WrapMonad a) = map WrapMonad (shrink a)
instance Arbitrary (a b c) => Arbitrary (WrappedArrow a b c) where
arbitrary = WrapArrow <$> arbitrary
shrink (WrapArrow a) = map WrapArrow (shrink a)
-- Arbitrary instances for Monoid
instance Arbitrary a => Arbitrary (Monoid.Dual a) where
arbitrary = fmap Monoid.Dual arbitrary
shrink = map Monoid.Dual . shrink . Monoid.getDual
instance (Arbitrary a, CoArbitrary a) => Arbitrary (Monoid.Endo a) where
arbitrary = fmap Monoid.Endo arbitrary
shrink = map Monoid.Endo . shrink . Monoid.appEndo
instance Arbitrary Monoid.All where
arbitrary = fmap Monoid.All arbitrary
shrink = map Monoid.All . shrink . Monoid.getAll
instance Arbitrary Monoid.Any where
arbitrary = fmap Monoid.Any arbitrary
shrink = map Monoid.Any . shrink . Monoid.getAny
instance Arbitrary a => Arbitrary (Monoid.Sum a) where
arbitrary = fmap Monoid.Sum arbitrary
shrink = map Monoid.Sum . shrink . Monoid.getSum
instance Arbitrary a => Arbitrary (Monoid.Product a) where
arbitrary = fmap Monoid.Product arbitrary
shrink = map Monoid.Product . shrink . Monoid.getProduct
#if defined(MIN_VERSION_base)
#if MIN_VERSION_base(3,0,0)
instance Arbitrary a => Arbitrary (Monoid.First a) where
arbitrary = fmap Monoid.First arbitrary
shrink = map Monoid.First . shrink . Monoid.getFirst
instance Arbitrary a => Arbitrary (Monoid.Last a) where
arbitrary = fmap Monoid.Last arbitrary
shrink = map Monoid.Last . shrink . Monoid.getLast
#endif
#if MIN_VERSION_base(4,8,0)
instance Arbitrary (f a) => Arbitrary (Monoid.Alt f a) where
arbitrary = fmap Monoid.Alt arbitrary
shrink = map Monoid.Alt . shrink . Monoid.getAlt
#endif
#endif
-- | Generates 'Version' with non-empty non-negative @versionBranch@, and empty @versionTags@
instance Arbitrary Version where
arbitrary = sized $ \n ->
do k <- choose (0, log2 n)
xs <- vectorOf (k+1) arbitrarySizedNatural
return (Version xs [])
where
log2 :: Int -> Int
log2 n | n <= 1 = 0
| otherwise = 1 + log2 (n `div` 2)
shrink (Version xs _) =
[ Version xs' []
| xs' <- shrink xs
, length xs' > 0
, all (>=0) xs'
]
instance Arbitrary QCGen where
arbitrary = MkGen (\g _ -> g)
instance Arbitrary ExitCode where
arbitrary = frequency [(1, return ExitSuccess), (3, liftM ExitFailure arbitrary)]
shrink (ExitFailure x) = ExitSuccess : [ ExitFailure x' | x' <- shrink x ]
shrink _ = []
-- ** Helper functions for implementing arbitrary
-- | Apply a binary function to random arguments.
applyArbitrary2 :: (Arbitrary a, Arbitrary b) => (a -> b -> r) -> Gen r
applyArbitrary2 f = liftA2 f arbitrary arbitrary
-- | Apply a ternary function to random arguments.
applyArbitrary3
:: (Arbitrary a, Arbitrary b, Arbitrary c)
=> (a -> b -> c -> r) -> Gen r
applyArbitrary3 f = liftA3 f arbitrary arbitrary arbitrary
-- | Apply a function of arity 4 to random arguments.
applyArbitrary4
:: (Arbitrary a, Arbitrary b, Arbitrary c, Arbitrary d)
=> (a -> b -> c -> d -> r) -> Gen r
applyArbitrary4 f = applyArbitrary3 (uncurry f)
-- | Generates an integral number. The number can be positive or negative
-- and its maximum absolute value depends on the size parameter.
arbitrarySizedIntegral :: Integral a => Gen a
arbitrarySizedIntegral =
sized $ \n ->
inBounds fromInteger (choose (-toInteger n, toInteger n))
-- | Generates a natural number. The number's maximum value depends on
-- the size parameter.
arbitrarySizedNatural :: Integral a => Gen a
arbitrarySizedNatural =
sized $ \n ->
inBounds fromInteger (choose (0, toInteger n))
inBounds :: Integral a => (Integer -> a) -> Gen Integer -> Gen a
inBounds fi g = fmap fi (g `suchThat` (\x -> toInteger (fi x) == x))
-- | Generates a fractional number. The number can be positive or negative
-- and its maximum absolute value depends on the size parameter.
arbitrarySizedFractional :: Fractional a => Gen a
arbitrarySizedFractional =
sized $ \n ->
let n' = toInteger n in
do b <- choose (1, precision)
a <- choose ((-n') * b, n' * b)
return (fromRational (a % b))
where
precision = 9999999999999 :: Integer
-- Useful for getting at minBound and maxBound without having to
-- fiddle around with asTypeOf.
withBounds :: Bounded a => (a -> a -> Gen a) -> Gen a
withBounds k = k minBound maxBound
-- | Generates an integral number. The number is chosen uniformly from
-- the entire range of the type. You may want to use
-- 'arbitrarySizedBoundedIntegral' instead.
arbitraryBoundedIntegral :: (Bounded a, Integral a) => Gen a
arbitraryBoundedIntegral =
withBounds $ \mn mx ->
do n <- choose (toInteger mn, toInteger mx)
return (fromInteger n)
-- | Generates an element of a bounded type. The element is
-- chosen from the entire range of the type.
arbitraryBoundedRandom :: (Bounded a, Random a) => Gen a
arbitraryBoundedRandom = choose (minBound,maxBound)
-- | Generates an element of a bounded enumeration.
arbitraryBoundedEnum :: (Bounded a, Enum a) => Gen a
arbitraryBoundedEnum =
withBounds $ \mn mx ->
do n <- choose (fromEnum mn, fromEnum mx)
return (toEnum n)
-- | Generates an integral number from a bounded domain. The number is
-- chosen from the entire range of the type, but small numbers are
-- generated more often than big numbers. Inspired by demands from
-- Phil Wadler.
arbitrarySizedBoundedIntegral :: (Bounded a, Integral a) => Gen a
arbitrarySizedBoundedIntegral =
withBounds $ \mn mx ->
sized $ \s ->
do let bits n | n == 0 = 0
| otherwise = 1 + bits (n `quot` 2)
k = (toInteger s*(bits mn `max` bits mx `max` 40) `div` 80)
-- computes x `min` (2^k), but avoids computing 2^k
-- if it is too large
x `minexp` k
| bits x < k = x
| otherwise = x `min` (2^k)
-- x `max` (-2^k)
x `maxexpneg` k = -((-x) `minexp` k)
n <- choose (toInteger mn `maxexpneg` k, toInteger mx `minexp` k)
return (fromInteger n)
-- ** Generators for various kinds of character
-- | Generates any Unicode character (but not a surrogate)
arbitraryUnicodeChar :: Gen Char
arbitraryUnicodeChar =
arbitraryBoundedEnum `suchThat` (not . isSurrogate)
where
isSurrogate c = generalCategory c == Surrogate
-- | Generates a random ASCII character (0-127).
arbitraryASCIIChar :: Gen Char
arbitraryASCIIChar = choose ('\0', '\127')
-- | Generates a printable Unicode character.
arbitraryPrintableChar :: Gen Char
arbitraryPrintableChar = arbitrary `suchThat` isPrint
-- ** Helper functions for implementing shrink
-- | Returns no shrinking alternatives.
shrinkNothing :: a -> [a]
shrinkNothing _ = []
-- | Map a shrink function to another domain. This is handy if your data type
-- has special invariants, but is /almost/ isomorphic to some other type.
--
-- @
-- shrinkOrderedList :: (Ord a, Arbitrary a) => [a] -> [[a]]
-- shrinkOrderedList = shrinkMap sort id
--
-- shrinkSet :: (Ord a, Arbitrary a) => Set a -> Set [a]
-- shrinkSet = shrinkMap fromList toList
-- @
shrinkMap :: Arbitrary a => (a -> b) -> (b -> a) -> b -> [b]
shrinkMap f g = shrinkMapBy f g shrink
-- | Non-overloaded version of `shrinkMap`.
shrinkMapBy :: (a -> b) -> (b -> a) -> (a -> [a]) -> b -> [b]
shrinkMapBy f g shr = map f . shr . g
-- | Shrink an integral number.
shrinkIntegral :: Integral a => a -> [a]
shrinkIntegral x =
nub $
[ -x
| x < 0, -x > x
] ++
[ x'
| x' <- takeWhile (<< x) (0:[ x - i | i <- tail (iterate (`quot` 2) x) ])
]
where
-- a << b is "morally" abs a < abs b, but taking care of overflow.
a << b = case (a >= 0, b >= 0) of
(True, True) -> a < b
(False, False) -> a > b
(True, False) -> a + b < 0
(False, True) -> a + b > 0
-- | Shrink a fraction, preferring numbers with smaller
-- numerators or denominators. See also 'shrinkDecimal'.
shrinkRealFrac :: RealFrac a => a -> [a]
shrinkRealFrac x
| not (x == x) = 0 : take 10 (iterate (*2) 0) -- NaN
| not (2*x+1>x) = 0 : takeWhile ( abs y < abs x) $
-- Try shrinking to an integer first
map fromInteger (shrink (truncate x) ++ [truncate x]) ++
-- Shrink the numerator
[fromRational (num' % denom) | num' <- shrink num] ++
-- Shrink the denominator, and keep the fraction as close
-- to the original as possible, rounding towards zero
[fromRational (truncate (num * denom' % denom) % denom')
| denom' <- shrink denom, denom' /= 0 ]
where
num = numerator (toRational x)
denom = denominator (toRational x)
-- | Shrink a real number, preferring numbers with shorter
-- decimal representations. See also 'shrinkRealFrac'.
shrinkDecimal :: RealFrac a => a -> [a]
shrinkDecimal x
| not (x == x) = 0 : take 10 (iterate (*2) 0) -- NaN
| not (2*x+1>x) = 0 : takeWhile ( instance CoArbitrary MyType
--
-- You should only use 'genericCoarbitrary' for data types where
-- equality is structural, i.e. if you can't have two different
-- representations of the same value. An example where it's not
-- safe is sets implemented using binary search trees: the same
-- set can be represented as several different trees.
-- Here you would have to explicitly define
-- @coarbitrary s = coarbitrary (toList s)@.
#else
-- | Used for random generation of functions.
#endif
class CoArbitrary a where
-- | Used to generate a function of type @a -> b@.
-- The first argument is a value, the second a generator.
-- You should use 'variant' to perturb the random generator;
-- the goal is that different values for the first argument will
-- lead to different calls to 'variant'. An example will help:
--
-- @
-- instance CoArbitrary a => CoArbitrary [a] where
-- coarbitrary [] = 'variant' 0
-- coarbitrary (x:xs) = 'variant' 1 . coarbitrary (x,xs)
-- @
coarbitrary :: a -> Gen b -> Gen b
#ifndef NO_GENERICS
default coarbitrary :: (Generic a, GCoArbitrary (Rep a)) => a -> Gen b -> Gen b
coarbitrary = genericCoarbitrary
-- | Generic CoArbitrary implementation.
genericCoarbitrary :: (Generic a, GCoArbitrary (Rep a)) => a -> Gen b -> Gen b
genericCoarbitrary = gCoarbitrary . from
class GCoArbitrary f where
gCoarbitrary :: f a -> Gen b -> Gen b
instance GCoArbitrary U1 where
gCoarbitrary U1 = id
instance (GCoArbitrary f, GCoArbitrary g) => GCoArbitrary (f :*: g) where
-- Like the instance for tuples.
gCoarbitrary (l :*: r) = gCoarbitrary l . gCoarbitrary r
instance (GCoArbitrary f, GCoArbitrary g) => GCoArbitrary (f :+: g) where
-- Like the instance for Either.
gCoarbitrary (L1 x) = variant 0 . gCoarbitrary x
gCoarbitrary (R1 x) = variant 1 . gCoarbitrary x
instance GCoArbitrary f => GCoArbitrary (M1 i c f) where
gCoarbitrary (M1 x) = gCoarbitrary x
instance CoArbitrary a => GCoArbitrary (K1 i a) where
gCoarbitrary (K1 x) = coarbitrary x
#endif
{-# DEPRECATED (><) "Use ordinary function composition instead" #-}
-- | Combine two generator perturbing functions, for example the
-- results of calls to 'variant' or 'coarbitrary'.
(><) :: (Gen a -> Gen a) -> (Gen a -> Gen a) -> (Gen a -> Gen a)
(><) = (.)
instance (Arbitrary a, CoArbitrary b) => CoArbitrary (a -> b) where
coarbitrary f gen =
do xs <- arbitrary
coarbitrary (map f xs) gen
instance CoArbitrary () where
coarbitrary _ = id
instance CoArbitrary Bool where
coarbitrary False = variant 0
coarbitrary True = variant 1
instance CoArbitrary Ordering where
coarbitrary GT = variant 0
coarbitrary EQ = variant 1
coarbitrary LT = variant 2
instance CoArbitrary a => CoArbitrary (Maybe a) where
coarbitrary Nothing = variant 0
coarbitrary (Just x) = variant 1 . coarbitrary x
instance (CoArbitrary a, CoArbitrary b) => CoArbitrary (Either a b) where
coarbitrary (Left x) = variant 0 . coarbitrary x
coarbitrary (Right y) = variant 1 . coarbitrary y
instance CoArbitrary a => CoArbitrary [a] where
coarbitrary [] = variant 0
coarbitrary (x:xs) = variant 1 . coarbitrary (x,xs)
instance (Integral a, CoArbitrary a) => CoArbitrary (Ratio a) where
coarbitrary r = coarbitrary (numerator r,denominator r)
#ifndef NO_FIXED
instance HasResolution a => CoArbitrary (Fixed a) where
coarbitrary = coarbitraryReal
#endif
instance (RealFloat a, CoArbitrary a) => CoArbitrary (Complex a) where
coarbitrary (x :+ y) = coarbitrary x . coarbitrary y
instance (CoArbitrary a, CoArbitrary b)
=> CoArbitrary (a,b)
where
coarbitrary (x,y) = coarbitrary x
. coarbitrary y
instance (CoArbitrary a, CoArbitrary b, CoArbitrary c)
=> CoArbitrary (a,b,c)
where
coarbitrary (x,y,z) = coarbitrary x
. coarbitrary y
. coarbitrary z
instance (CoArbitrary a, CoArbitrary b, CoArbitrary c, CoArbitrary d)
=> CoArbitrary (a,b,c,d)
where
coarbitrary (x,y,z,v) = coarbitrary x
. coarbitrary y
. coarbitrary z
. coarbitrary v
instance (CoArbitrary a, CoArbitrary b, CoArbitrary c, CoArbitrary d, CoArbitrary e)
=> CoArbitrary (a,b,c,d,e)
where
coarbitrary (x,y,z,v,w) = coarbitrary x
. coarbitrary y
. coarbitrary z
. coarbitrary v
. coarbitrary w
-- typical instance for primitive (numerical) types
instance CoArbitrary Integer where
coarbitrary = coarbitraryIntegral
instance CoArbitrary Int where
coarbitrary = coarbitraryIntegral
instance CoArbitrary Int8 where
coarbitrary = coarbitraryIntegral
instance CoArbitrary Int16 where
coarbitrary = coarbitraryIntegral
instance CoArbitrary Int32 where
coarbitrary = coarbitraryIntegral
instance CoArbitrary Int64 where
coarbitrary = coarbitraryIntegral
instance CoArbitrary Word where
coarbitrary = coarbitraryIntegral
instance CoArbitrary Word8 where
coarbitrary = coarbitraryIntegral
instance CoArbitrary Word16 where
coarbitrary = coarbitraryIntegral
instance CoArbitrary Word32 where
coarbitrary = coarbitraryIntegral
instance CoArbitrary Word64 where
coarbitrary = coarbitraryIntegral
instance CoArbitrary Char where
coarbitrary = coarbitrary . ord
instance CoArbitrary Float where
coarbitrary = coarbitraryReal
instance CoArbitrary Double where
coarbitrary = coarbitraryReal
-- Coarbitrary instances for container types
instance CoArbitrary a => CoArbitrary (Set.Set a) where
coarbitrary = coarbitrary. Set.toList
instance (CoArbitrary k, CoArbitrary v) => CoArbitrary (Map.Map k v) where
coarbitrary = coarbitrary . Map.toList
instance CoArbitrary IntSet.IntSet where
coarbitrary = coarbitrary . IntSet.toList
instance CoArbitrary a => CoArbitrary (IntMap.IntMap a) where
coarbitrary = coarbitrary . IntMap.toList
instance CoArbitrary a => CoArbitrary (Sequence.Seq a) where
coarbitrary = coarbitrary . toList
-- CoArbitrary instance for Ziplist
instance CoArbitrary a => CoArbitrary (ZipList a) where
coarbitrary = coarbitrary . getZipList
#ifndef NO_TRANSFORMERS
-- CoArbitrary instance for transformers' Functors
instance CoArbitrary a => CoArbitrary (Identity a) where
coarbitrary = coarbitrary . runIdentity
instance CoArbitrary a => CoArbitrary (Constant a b) where
coarbitrary = coarbitrary . getConstant
#endif
-- CoArbitrary instance for Const
instance CoArbitrary a => CoArbitrary (Const a b) where
coarbitrary = coarbitrary . getConst
-- CoArbitrary instances for Monoid
instance CoArbitrary a => CoArbitrary (Monoid.Dual a) where
coarbitrary = coarbitrary . Monoid.getDual
instance (Arbitrary a, CoArbitrary a) => CoArbitrary (Monoid.Endo a) where
coarbitrary = coarbitrary . Monoid.appEndo
instance CoArbitrary Monoid.All where
coarbitrary = coarbitrary . Monoid.getAll
instance CoArbitrary Monoid.Any where
coarbitrary = coarbitrary . Monoid.getAny
instance CoArbitrary a => CoArbitrary (Monoid.Sum a) where
coarbitrary = coarbitrary . Monoid.getSum
instance CoArbitrary a => CoArbitrary (Monoid.Product a) where
coarbitrary = coarbitrary . Monoid.getProduct
#if defined(MIN_VERSION_base)
#if MIN_VERSION_base(3,0,0)
instance CoArbitrary a => CoArbitrary (Monoid.First a) where
coarbitrary = coarbitrary . Monoid.getFirst
instance CoArbitrary a => CoArbitrary (Monoid.Last a) where
coarbitrary = coarbitrary . Monoid.getLast
#endif
#if MIN_VERSION_base(4,8,0)
instance CoArbitrary (f a) => CoArbitrary (Monoid.Alt f a) where
coarbitrary = coarbitrary . Monoid.getAlt
#endif
#endif
instance CoArbitrary Version where
coarbitrary (Version a b) = coarbitrary (a, b)
-- ** Helpers for implementing coarbitrary
-- | A 'coarbitrary' implementation for integral numbers.
coarbitraryIntegral :: Integral a => a -> Gen b -> Gen b
coarbitraryIntegral = variant
-- | A 'coarbitrary' implementation for real numbers.
coarbitraryReal :: Real a => a -> Gen b -> Gen b
coarbitraryReal x = coarbitrary (toRational x)
-- | 'coarbitrary' helper for lazy people :-).
coarbitraryShow :: Show a => a -> Gen b -> Gen b
coarbitraryShow x = coarbitrary (show x)
-- | A 'coarbitrary' implementation for enums.
coarbitraryEnum :: Enum a => a -> Gen b -> Gen b
coarbitraryEnum = variant . fromEnum
--------------------------------------------------------------------------
-- ** arbitrary generators
-- these are here and not in Gen because of the Arbitrary class constraint
-- | Generates a list of a given length.
vector :: Arbitrary a => Int -> Gen [a]
vector k = vectorOf k arbitrary
-- | Generates an ordered list.
orderedList :: (Ord a, Arbitrary a) => Gen [a]
orderedList = sort `fmap` arbitrary
-- | Generates an infinite list.
infiniteList :: Arbitrary a => Gen [a]
infiniteList = infiniteListOf arbitrary
--------------------------------------------------------------------------
-- the end.