Test.QuickCheck.Arbitrary.Generic

generic-arbitrary-1.0.1: Generic implementation for QuickCheck's Arbitrary

Safe Haskell | None
Language | Haskell2010

Test.QuickCheck.Arbitrary.Generic

Contents

- Main
- Internal
- Reexports

Description

This module is a generic implementation of the `arbitrary` method. Example usage:

    data Foo = Foo
      { _fooX :: X
      , _fooY :: Y
      } deriving (Generic)

    instance Arbitrary Foo where
      arbitrary = genericArbitrary
      shrink = genericShrink

This instance can also be derived using DerivingVia language extension

    data Foo = Foo
      { _fooX :: X
      , _fooY :: Y
      } deriving (Generic)
        deriving (Arbitrary) via GenericArbitrary Foo

The generated `arbitrary` method is equivalent to

    Foo <$> arbitrary <*> arbitrary

.

It can also handle a recursive types problem. Assuming a type

    data R = R R
      deriving Generic

there is no instance

    instance Arbitrary R where
      arbitrary = genericArbitrary
      shrink = genericShrink

If you try to compile this you will get a type level error

       • R refers to itself in all constructors

Which means that there is no finite term for `R` because it is recursive. But, if you correct the definition of `R` like this.

    data R = R R | F
      deriving Generic

Then it will compile. And the `arbitrary` generated will not hang forever, because it respects the `size` parameter.

There is a limitation of recursion detection:

    data R1 = R1 R2
      deriving (Eq, Ord, Show, Generic)
      deriving anyclass NFData
      deriving Arbitrary via (GenericArbitrary R1)

    data R2 = R2 R1
      deriving (Eq, Ord, Show, Generic)
      deriving anyclass NFData
      deriving Arbitrary via (GenericArbitrary R2)

This code will compile and the `arbitrary` generated will always hang. Yes, there is a problem with mutually recursive types.

Now lets see an example of datatype with parameters

    data A a = A a
      deriving (Eq, Ord, Show)
      deriving anyclass NFData
      deriving (Generic)

    instance (Arbitrary a) => Arbitrary (A a) where
      arbitrary = genericArbitrary
      shrink = genericShrink

It should work from first glance, but when compile it will throw an error:

        • Could not deduce (Test.QuickCheck.Arbitrary.Generic.GArbitrary
                              (A a)
                              (GHC.Generics.D1
                                 ('GHC.Generics.MetaData A ParametersTest "main" 'False)
                                 (GHC.Generics.C1
                                    ('GHC.Generics.MetaCons A 'GHC.Generics.PrefixI 'False)
                                    (GHC.Generics.S1
                                       ('GHC.Generics.MetaSel
                                          'Nothing
                                          'GHC.Generics.NoSourceUnpackedness
                                          'GHC.Generics.NoSourceStrictness
                                          'GHC.Generics.DecidedLazy)
                                       (GHC.Generics.Rec0 a))))
                              (TypesDiffer (A a) a))
            arising from a use of ‘genericArbitrary’

Here the `TypesDiffer` is a type familty dealing with recursive types and helping us to eliminate inproper instances. To convince the compiller, that the `a` parameter is not an `A a` we must fix the instance with additional constraint

    instance (Arg (A a) a, Arbitrary a) => Arbitrary (A a) where
      arbitrary = genericArbitrary
      shrink = genericShrink

Now everything compiles and works as expected.

Synopsis

- genericArbitrary :: forall a (ga :: Type -> Type) (some :: Bool). (Generic a, GArbitrary a ga some, ga ~ Rep a) => Gen a
- newtype GenericArbitrary a = GenericArbitrary {
  - unGenericArbitrary :: a
  }
- type Arg (self :: k) (field :: k) = TypesDiffer self field ~ 'True
- class Finite self a ~ finite => GArbitrary self (a :: Type -> Type) (finite :: Bool)
- class (Finite self a ~ af, Finite self b ~ bf) => FiniteSum self (a :: Type -> Type) (b :: Type -> Type) (af :: Bool) (bf :: Bool)
- class FiniteSumElem (self :: k) (a :: k1 -> Type)
- type family Finite self (a :: Type -> Type) :: Bool where ...
- type family AllFieldsFinal self (a :: Type -> Type) :: Bool where ...
- type family TypesDiffer (a :: k) (b :: k) :: Bool where ...
- type family ArgumentsCount (a :: Type -> Type) :: Nat where ...
- type family SumLen (a :: k -> Type) :: Nat where ...
- class Arbitrary a where
  - arbitrary :: Gen a
  - shrink :: a -> [a]
- genericShrink :: (Generic a, RecursivelyShrink (Rep a), GSubterms (Rep a) a) => a -> [a]

# Main

genericArbitrary :: forall a (ga :: Type -> Type) (some :: Bool). (Generic a, GArbitrary a ga some, ga ~ Rep a) => Gen a #

newtype GenericArbitrary a #

Newtype for `DerivingVia`

Usage:

    data Foo = Foo
      { _fooX :: X
      , _fooY :: Y
      } deriving (Generic)
        deriving (Arbitrary) via GenericArbitrary Foo

Since: 1.0.0

Constructors

GenericArbitrary |
Fields unGenericArbitrary :: a

#### Instances

Instances details

(Generic a, GArbitrary a (Rep a) some, RecursivelyShrink (Rep a), GSubterms (Rep a) a) => Arbitrary (GenericArbitrary a) # |
Instance details Defined in Test.QuickCheck.Arbitrary.Generic Methods arbitrary :: Gen (GenericArbitrary a) # shrink :: GenericArbitrary a -> [GenericArbitrary a] #
Show a => Show (GenericArbitrary a) # |
Instance details Defined in Test.QuickCheck.Arbitrary.Generic Methods showsPrec :: Int -> GenericArbitrary a -> ShowS # show :: GenericArbitrary a -> String # showList :: [GenericArbitrary a] -> ShowS #
Eq a => Eq (GenericArbitrary a) # |
Instance details Defined in Test.QuickCheck.Arbitrary.Generic Methods (==) :: GenericArbitrary a -> GenericArbitrary a -> Bool # (/=) :: GenericArbitrary a -> GenericArbitrary a -> Bool #

type Arg (self :: k) (field :: k) = TypesDiffer self field ~ 'True #

Constraint helper for types with parameters

Usage:

    data A a = A a
      deriving (Generic)
    instance (Arg (A a) a, Arbitrary a) => Arbitrary (A a) where
      arbitrary = genericArbitrary
      shrink = genericShrink

Since: 1.0.0

# Internal

class Finite self a ~ finite => GArbitrary self (a :: Type -> Type) (finite :: Bool) #

Generic arbitrary.

Parameters are: * self: the ADT we generating instance for * a: some part of the `Rep self` * finite: Is `a` finite? Infinite type has no finite values (like Stream)

Minimal complete definition

gArbitrary

#### Instances

Instances details

GArbitrary self (U1 :: Type -> Type) 'True # | Unit type instance
Instance details Defined in Test.QuickCheck.Arbitrary.Generic Methods gArbitrary :: Proxy self -> Gen (U1 x)
(GArbitrary self a af, GArbitrary self b bf, (af && bf) ~ some) => GArbitrary self (a :*: b) some # | Product
Instance details Defined in Test.QuickCheck.Arbitrary.Generic Methods gArbitrary :: Proxy self -> Gen ((a :*: b) x)
(GArbitrary self a af, GArbitrary self b bf, KnownNat (SumLen a), KnownNat (SumLen b), (af || bf) ~ some) => GArbitrary self (a :+: b) some # | Any sum inside of declaration
Instance details Defined in Test.QuickCheck.Arbitrary.Generic Methods gArbitrary :: Proxy self -> Gen ((a :+: b) x)
(Arbitrary t, Finite self (K1 R t :: Type -> Type) ~ some) => GArbitrary self (K1 R t :: Type -> Type) some # | Data of the constructor field
Instance details Defined in Test.QuickCheck.Arbitrary.Generic Methods gArbitrary :: Proxy self -> Gen (K1 R t x)
(GArbitrary self f some, KnownNat (ArgumentsCount f), AllFieldsFinal self f ~ some) => GArbitrary self (M1 C c f) some # | The constructor meta information
Instance details Defined in Test.QuickCheck.Arbitrary.Generic Methods gArbitrary :: Proxy self -> Gen (M1 C c f x)
(TypeError ('ShowType self ':<>: 'Text " refers to itself in all constructors") :: Constraint, (Finite self a || Finite self b) ~ 'False) => GArbitrary self (M1 D t (a :+: b)) 'False # |
Instance details Defined in Test.QuickCheck.Arbitrary.Generic Methods gArbitrary :: Proxy self -> Gen (M1 D t (a :+: b) x)
(FiniteSum self a b af bf, GArbitrary self (a :+: b) 'True) => GArbitrary self (M1 D t (a :+: b)) 'True # | ADT declaration with multiple constructors
Instance details Defined in Test.QuickCheck.Arbitrary.Generic Methods gArbitrary :: Proxy self -> Gen (M1 D t (a :+: b) x)
(TypeError ('ShowType self ':<>: 'Text " refers to itself in all constructors") :: Constraint, AllFieldsFinal self f ~ 'False) => GArbitrary self (M1 D t (M1 C c f)) 'False # |
Instance details Defined in Test.QuickCheck.Arbitrary.Generic Methods gArbitrary :: Proxy self -> Gen (M1 D t (M1 C c f) x)
GArbitrary self (M1 C c f) 'True => GArbitrary self (M1 D t (M1 C c f)) 'True # |
Instance details Defined in Test.QuickCheck.Arbitrary.Generic Methods gArbitrary :: Proxy self -> Gen (M1 D t (M1 C c f) x)
GArbitrary self f some => GArbitrary self (M1 S t f) some # | Constructor field meta information
Instance details Defined in Test.QuickCheck.Arbitrary.Generic Methods gArbitrary :: Proxy self -> Gen (M1 S t f x)

class (Finite self a ~ af, Finite self b ~ bf) => FiniteSum self (a :: Type -> Type) (b :: Type -> Type) (af :: Bool) (bf :: Bool) #

Minimal complete definition

finiteSum

#### Instances

Instances details

(FiniteSumElem self b, Finite self a ~ 'False, Finite self b ~ 'True) => FiniteSum self a b 'False 'True # |
Instance details Defined in Test.QuickCheck.Arbitrary.Generic Methods finiteSum :: Proxy self -> [Gen ((a :+: b) p)]
(FiniteSumElem self a, Finite self a ~ 'True, Finite self b ~ 'False) => FiniteSum self a b 'True 'False # |
Instance details Defined in Test.QuickCheck.Arbitrary.Generic Methods finiteSum :: Proxy self -> [Gen ((a :+: b) p)]
(FiniteSumElem self a, FiniteSumElem self b, Finite self a ~ 'True, Finite self b ~ 'True) => FiniteSum self a b 'True 'True # |
Instance details Defined in Test.QuickCheck.Arbitrary.Generic Methods finiteSum :: Proxy self -> [Gen ((a :+: b) p)]

class FiniteSumElem (self :: k) (a :: k1 -> Type) #

Minimal complete definition

finiteElem

#### Instances

Instances details

FiniteSum self a b af bf => FiniteSumElem (self :: Type) (a :+: b :: Type -> Type) # |
Instance details Defined in Test.QuickCheck.Arbitrary.Generic Methods finiteElem :: Proxy self -> [Gen ((a :+: b) p)]
GArbitrary self (M1 C c f) 'True => FiniteSumElem (self :: Type) (M1 C c f :: Type -> Type) # |
Instance details Defined in Test.QuickCheck.Arbitrary.Generic Methods finiteElem :: Proxy self -> [Gen (M1 C c f p)]

type family Finite self (a :: Type -> Type) :: Bool where ... #

Equations

Finite self (U1 :: Type -> Type) = 'True |
Finite self (K1 R field :: Type -> Type) = TypesDiffer self field |
Finite self (a :*: b) = Finite self a && Finite self b |
Finite self (M1 D t f) = Finite self f |
Finite self (a :+: b) = Finite self a || Finite self b |
Finite self (M1 C c f) = AllFieldsFinal self f |
Finite self (M1 S s f) = Finite self f |

type family AllFieldsFinal self (a :: Type -> Type) :: Bool where ... #

Equations

AllFieldsFinal self (U1 :: Type -> Type) = 'True |
AllFieldsFinal self (a :*: b) = AllFieldsFinal self a && AllFieldsFinal self b |
AllFieldsFinal self (M1 S t (K1 R field :: Type -> Type)) = TypesDiffer self field |

type family TypesDiffer (a :: k) (b :: k) :: Bool where ... #

Equations

TypesDiffer (a :: k) (a :: k) = 'False |
TypesDiffer (a :: k) (b :: k) = 'True |

type family ArgumentsCount (a :: Type -> Type) :: Nat where ... #

Equations

ArgumentsCount (U1 :: Type -> Type) = 1 |
ArgumentsCount (M1 S s f) = 1 |
ArgumentsCount (a :*: b) = ArgumentsCount a + ArgumentsCount b |

type family SumLen (a :: k -> Type) :: Nat where ... #

Calculates count of constructors encoded by particular `:+:`. Internal use only.

Equations

SumLen (a :+: b :: k -> Type) = SumLen a + SumLen b |
SumLen (a :: k -> Type) = 1 |

# Reexports

class Arbitrary a where #

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 quickcheck-instances package.

Minimal complete definition

arbitrary

Methods

arbitrary :: Gen a #

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 testing-feat or generic-random packages.

The QuickCheck manual goes into detail on how to write good generators. Make sure to look at it, especially if your type is recursive!

shrink :: a -> [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.

#### Instances

Instances details

Arbitrary ASCIIString |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen ASCIIString # shrink :: ASCIIString -> [ASCIIString] #
Arbitrary PrintableString |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen PrintableString # shrink :: PrintableString -> [PrintableString] #
Arbitrary UnicodeString |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen UnicodeString # shrink :: UnicodeString -> [UnicodeString] #
Arbitrary A |
Instance details Defined in Test.QuickCheck.Poly Methods arbitrary :: Gen A # shrink :: A -> [A] #
Arbitrary B |
Instance details Defined in Test.QuickCheck.Poly Methods arbitrary :: Gen B # shrink :: B -> [B] #
Arbitrary C |
Instance details Defined in Test.QuickCheck.Poly Methods arbitrary :: Gen C # shrink :: C -> [C] #
Arbitrary OrdA |
Instance details Defined in Test.QuickCheck.Poly Methods arbitrary :: Gen OrdA # shrink :: OrdA -> [OrdA] #
Arbitrary OrdB |
Instance details Defined in Test.QuickCheck.Poly Methods arbitrary :: Gen OrdB # shrink :: OrdB -> [OrdB] #
Arbitrary OrdC |
Instance details Defined in Test.QuickCheck.Poly Methods arbitrary :: Gen OrdC # shrink :: OrdC -> [OrdC] #
Arbitrary QCGen |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen QCGen # shrink :: QCGen -> [QCGen] #
Arbitrary IntSet | WARNING: The same warning as for `Arbitrary (Set a)` applies here.
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen IntSet # shrink :: IntSet -> [IntSet] #
Arbitrary All |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen All # shrink :: All -> [All] #
Arbitrary Any |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen Any # shrink :: Any -> [Any] #
Arbitrary Version | Generates `Version` with non-empty non-negative `versionBranch`, and empty `versionTags`
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen Version # shrink :: Version -> [Version] #
Arbitrary CChar |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CChar # shrink :: CChar -> [CChar] #
Arbitrary CClock |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CClock # shrink :: CClock -> [CClock] #
Arbitrary CDouble |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CDouble # shrink :: CDouble -> [CDouble] #
Arbitrary CFloat |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CFloat # shrink :: CFloat -> [CFloat] #
Arbitrary CInt |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CInt # shrink :: CInt -> [CInt] #
Arbitrary CIntMax |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CIntMax # shrink :: CIntMax -> [CIntMax] #
Arbitrary CIntPtr |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CIntPtr # shrink :: CIntPtr -> [CIntPtr] #
Arbitrary CLLong |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CLLong # shrink :: CLLong -> [CLLong] #
Arbitrary CLong |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CLong # shrink :: CLong -> [CLong] #
Arbitrary CPtrdiff |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CPtrdiff # shrink :: CPtrdiff -> [CPtrdiff] #
Arbitrary CSChar |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CSChar # shrink :: CSChar -> [CSChar] #
Arbitrary CSUSeconds |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CSUSeconds # shrink :: CSUSeconds -> [CSUSeconds] #
Arbitrary CShort |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CShort # shrink :: CShort -> [CShort] #
Arbitrary CSigAtomic |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CSigAtomic # shrink :: CSigAtomic -> [CSigAtomic] #
Arbitrary CSize |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CSize # shrink :: CSize -> [CSize] #
Arbitrary CTime |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CTime # shrink :: CTime -> [CTime] #
Arbitrary CUChar |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CUChar # shrink :: CUChar -> [CUChar] #
Arbitrary CUInt |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CUInt # shrink :: CUInt -> [CUInt] #
Arbitrary CUIntMax |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CUIntMax # shrink :: CUIntMax -> [CUIntMax] #
Arbitrary CUIntPtr |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CUIntPtr # shrink :: CUIntPtr -> [CUIntPtr] #
Arbitrary CULLong |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CULLong # shrink :: CULLong -> [CULLong] #
Arbitrary CULong |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CULong # shrink :: CULong -> [CULong] #
Arbitrary CUSeconds |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CUSeconds # shrink :: CUSeconds -> [CUSeconds] #
Arbitrary CUShort |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CUShort # shrink :: CUShort -> [CUShort] #
Arbitrary CWchar |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen CWchar # shrink :: CWchar -> [CWchar] #
Arbitrary ExitCode |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen ExitCode # shrink :: ExitCode -> [ExitCode] #
Arbitrary Newline |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen Newline # shrink :: Newline -> [Newline] #
Arbitrary NewlineMode |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen NewlineMode # shrink :: NewlineMode -> [NewlineMode] #
Arbitrary Int16 |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen Int16 # shrink :: Int16 -> [Int16] #
Arbitrary Int32 |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen Int32 # shrink :: Int32 -> [Int32] #
Arbitrary Int64 |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen Int64 # shrink :: Int64 -> [Int64] #
Arbitrary Int8 |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen Int8 # shrink :: Int8 -> [Int8] #
Arbitrary Word16 |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen Word16 # shrink :: Word16 -> [Word16] #
Arbitrary Word32 |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen Word32 # shrink :: Word32 -> [Word32] #
Arbitrary Word64 |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen Word64 # shrink :: Word64 -> [Word64] #
Arbitrary Word8 |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen Word8 # shrink :: Word8 -> [Word8] #
Arbitrary Ordering |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen Ordering # shrink :: Ordering -> [Ordering] #
Arbitrary Integer |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen Integer # shrink :: Integer -> [Integer] #
Arbitrary () |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen () # shrink :: () -> [()] #
Arbitrary Bool |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen Bool # shrink :: Bool -> [Bool] #
Arbitrary Char |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen Char # shrink :: Char -> [Char] #
Arbitrary Double |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen Double # shrink :: Double -> [Double] #
Arbitrary Float |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen Float # shrink :: Float -> [Float] #
Arbitrary Int |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen Int # shrink :: Int -> [Int] #
Arbitrary Word |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen Word # shrink :: Word -> [Word] #
Arbitrary a => Arbitrary (Blind a) |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen (Blind a) # shrink :: Blind a -> [Blind a] #
Arbitrary a => Arbitrary (Fixed a) |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen (Fixed a) # shrink :: Fixed a -> [Fixed a] #
Arbitrary a => Arbitrary (InfiniteList a) |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen (InfiniteList a) # shrink :: InfiniteList a -> [InfiniteList a] #
Arbitrary a => Arbitrary (InfiniteListInternalData a) |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen (InfiniteListInternalData a) # shrink :: InfiniteListInternalData a -> [InfiniteListInternalData a] #
(Integral a, Bounded a) => Arbitrary (Large a) |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen (Large a) # shrink :: Large a -> [Large a] #
(Num a, Ord a, Arbitrary a) => Arbitrary (Negative a) |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen (Negative a) # shrink :: Negative a -> [Negative a] #
Arbitrary a => Arbitrary (NonEmptyList a) |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen (NonEmptyList a) # shrink :: NonEmptyList a -> [NonEmptyList a] #
(Num a, Ord a, Arbitrary a) => Arbitrary (NonNegative a) |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen (NonNegative a) # shrink :: NonNegative a -> [NonNegative a] #
(Num a, Ord a, Arbitrary a) => Arbitrary (NonPositive a) |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen (NonPositive a) # shrink :: NonPositive a -> [NonPositive a] #
(Num a, Eq a, Arbitrary a) => Arbitrary (NonZero a) |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen (NonZero a) # shrink :: NonZero a -> [NonZero a] #
(Ord a, Arbitrary a) => Arbitrary (OrderedList a) |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen (OrderedList a) # shrink :: OrderedList a -> [OrderedList a] #
(Num a, Ord a, Arbitrary a) => Arbitrary (Positive a) |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen (Positive a) # shrink :: Positive a -> [Positive a] #
Arbitrary a => Arbitrary (Shrink2 a) |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen (Shrink2 a) # shrink :: Shrink2 a -> [Shrink2 a] #
Integral a => Arbitrary (Small a) |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen (Small a) # shrink :: Small a -> [Small a] #
Arbitrary a => Arbitrary (Smart a) |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen (Smart a) # shrink :: Smart a -> [Smart a] #
(Arbitrary a, Ord a) => Arbitrary (SortedList a) |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen (SortedList a) # shrink :: SortedList a -> [SortedList a] #
Arbitrary a => Arbitrary (Complex a) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Complex a) # shrink :: Complex a -> [Complex a] #
Arbitrary a => Arbitrary (IntMap a) | WARNING: The same warning as for `Arbitrary (Set a)` applies here.
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (IntMap a) # shrink :: IntMap a -> [IntMap a] #
Arbitrary a => Arbitrary (Seq a) | WARNING: The same warning as for `Arbitrary (Set a)` applies here.
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Seq a) # shrink :: Seq a -> [Seq a] #
(Ord a, Arbitrary a) => Arbitrary (Set a) | WARNING: Users working on the internals of the `Set` type via e.g. `Data.Set.Internal` should be aware that this instance aims to give a good representation of `Set a` as mathematical sets but *does not* aim to provide a varied distribution over the underlying representation.
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Set a) # shrink :: Set a -> [Set a] #
Arbitrary a => Arbitrary (Tree a) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Tree a) # shrink :: Tree a -> [Tree a] #
(Generic a, GArbitrary a (Rep a) some, RecursivelyShrink (Rep a), GSubterms (Rep a) a) => Arbitrary (GenericArbitrary a) # |
Instance details Defined in Test.QuickCheck.Arbitrary.Generic Methods arbitrary :: Gen (GenericArbitrary a) # shrink :: GenericArbitrary a -> [GenericArbitrary a] #
Arbitrary a => Arbitrary (Identity a) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Identity a) # shrink :: Identity a -> [Identity a] #
Arbitrary a => Arbitrary (First a) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (First a) # shrink :: First a -> [First a] #
Arbitrary a => Arbitrary (Last a) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Last a) # shrink :: Last a -> [Last a] #
Arbitrary a => Arbitrary (Dual a) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Dual a) # shrink :: Dual a -> [Dual a] #
(Arbitrary a, CoArbitrary a) => Arbitrary (Endo a) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Endo a) # shrink :: Endo a -> [Endo a] #
Arbitrary a => Arbitrary (Product a) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Product a) # shrink :: Product a -> [Product a] #
Arbitrary a => Arbitrary (Sum a) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Sum a) # shrink :: Sum a -> [Sum a] #
Arbitrary a => Arbitrary (ZipList a) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (ZipList a) # shrink :: ZipList a -> [ZipList a] #
Integral a => Arbitrary (Ratio a) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Ratio a) # shrink :: Ratio a -> [Ratio a] #
Arbitrary a => Arbitrary (Maybe a) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Maybe a) # shrink :: Maybe a -> [Maybe a] #
Arbitrary a => Arbitrary [a] |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen [a] # shrink :: [a] -> [[a]] #
(Function a, CoArbitrary a, Arbitrary b) => Arbitrary (a :-> b) |
Instance details Defined in Test.QuickCheck.Function Methods arbitrary :: Gen (a :-> b) # shrink :: (a :-> b) -> [a :-> b] #
(Function a, CoArbitrary a, Arbitrary b) => Arbitrary (Fun a b) |
Instance details Defined in Test.QuickCheck.Function Methods arbitrary :: Gen (Fun a b) # shrink :: Fun a b -> [Fun a b] #
(Arbitrary a, ShrinkState s a) => Arbitrary (Shrinking s a) |
Instance details Defined in Test.QuickCheck.Modifiers Methods arbitrary :: Gen (Shrinking s a) # shrink :: Shrinking s a -> [Shrinking s a] #
Arbitrary (m a) => Arbitrary (WrappedMonad m a) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (WrappedMonad m a) # shrink :: WrappedMonad m a -> [WrappedMonad m a] #
HasResolution a => Arbitrary (Fixed a) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Fixed a) # shrink :: Fixed a -> [Fixed a] #
(Ord k, Arbitrary k, Arbitrary v) => Arbitrary (Map k v) | WARNING: The same warning as for `Arbitrary (Set a)` applies here.
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Map k v) # shrink :: Map k v -> [Map k v] #
(Arbitrary a, Arbitrary b) => Arbitrary (Either a b) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Either a b) # shrink :: Either a b -> [Either a b] #
(Arbitrary a, Arbitrary b) => Arbitrary (a, b) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (a, b) # shrink :: (a, b) -> [(a, b)] #
(CoArbitrary a, Arbitrary b) => Arbitrary (a -> b) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (a -> b) # shrink :: (a -> b) -> [a -> b] #
Arbitrary (a b c) => Arbitrary (WrappedArrow a b c) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (WrappedArrow a b c) # shrink :: WrappedArrow a b c -> [WrappedArrow a b c] #
Arbitrary a => Arbitrary (Const a b) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Const a b) # shrink :: Const a b -> [Const a b] #
Arbitrary (f a) => Arbitrary (Alt f a) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Alt f a) # shrink :: Alt f a -> [Alt f a] #
Arbitrary a => Arbitrary (Constant a b) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Constant a b) # shrink :: Constant a b -> [Constant a b] #
(Arbitrary a, Arbitrary b, Arbitrary c) => Arbitrary (a, b, c) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (a, b, c) # shrink :: (a, b, c) -> [(a, b, c)] #
(Arbitrary1 f, Arbitrary1 g, Arbitrary a) => Arbitrary (Product f g a) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Product f g a) # shrink :: Product f g a -> [Product f g a] #
(Arbitrary a, Arbitrary b, Arbitrary c, Arbitrary d) => Arbitrary (a, b, c, d) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (a, b, c, d) # shrink :: (a, b, c, d) -> [(a, b, c, d)] #
(Arbitrary1 f, Arbitrary1 g, Arbitrary a) => Arbitrary (Compose f g a) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (Compose f g a) # shrink :: Compose f g a -> [Compose f g a] #
(Arbitrary a, Arbitrary b, Arbitrary c, Arbitrary d, Arbitrary e) => Arbitrary (a, b, c, d, e) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (a, b, c, d, e) # shrink :: (a, b, c, d, e) -> [(a, b, c, d, e)] #
(Arbitrary a, Arbitrary b, Arbitrary c, Arbitrary d, Arbitrary e, Arbitrary f) => Arbitrary (a, b, c, d, e, f) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (a, b, c, d, e, f) # shrink :: (a, b, c, d, e, f) -> [(a, b, c, d, e, f)] #
(Arbitrary a, Arbitrary b, Arbitrary c, Arbitrary d, Arbitrary e, Arbitrary f, Arbitrary g) => Arbitrary (a, b, c, d, e, f, g) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (a, b, c, d, e, f, g) # shrink :: (a, b, c, d, e, f, g) -> [(a, b, c, d, e, f, g)] #
(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) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (a, b, c, d, e, f, g, h) # shrink :: (a, b, c, d, e, f, g, h) -> [(a, b, c, d, e, f, g, h)] #
(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) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (a, b, c, d, e, f, g, h, i) # shrink :: (a, b, c, d, e, f, g, h, i) -> [(a, b, c, d, e, f, g, h, i)] #
(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) |
Instance details Defined in Test.QuickCheck.Arbitrary Methods arbitrary :: Gen (a, b, c, d, e, f, g, h, i, j) # shrink :: (a, b, c, d, e, f, g, h, i, j) -> [(a, b, c, d, e, f, g, h, i, j)] #

genericShrink :: (Generic a, RecursivelyShrink (Rep a), GSubterms (Rep a) a) => a -> [a] #

Shrink a term to any of its immediate subterms, and also recursively shrink all subterms.