QuickCheck-2.6: Automatic testing of Haskell programs

Safe Haskell | Safe-Inferred
Language | Haskell98

Test.QuickCheck.Arbitrary

Contents

- Arbitrary and CoArbitrary classes
  - Helper functions for implementing arbitrary
  - Helper functions for implementing shrink
  - Helper functions for implementing coarbitrary
  - Generators which use arbitrary

Synopsis

- class Arbitrary a where
  - arbitrary :: Gen a
  - shrink :: a -> [a]
- class CoArbitrary a where
  - coarbitrary :: a -> Gen c -> Gen c
- arbitrarySizedIntegral :: Num 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
- shrinkNothing :: a -> [a]
- shrinkList :: (a -> [a]) -> [a] -> [[a]]
- shrinkIntegral :: Integral a => a -> [a]
- shrinkRealFrac :: RealFrac a => a -> [a]
- (><) :: (Gen a -> Gen a) -> (Gen a -> Gen a) -> Gen a -> Gen a
- 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
- vector :: Arbitrary a => Int -> Gen [a]
- orderedList :: (Ord a, Arbitrary a) => Gen [a]

# Arbitrary and CoArbitrary classes

class Arbitrary a where

Random generation and shrinking of values.

Minimal complete definition

Nothing

Methods

arbitrary :: Gen a

A generator for values of the given type.

shrink :: a -> [a]

Produces a (possibly) empty list of all the possible immediate shrinks of the given value.

Instances

Arbitrary Bool |
Arbitrary Char |
Arbitrary Double |
Arbitrary Float |
Arbitrary Int |
Arbitrary Int8 |
Arbitrary Int16 |
Arbitrary Int32 |
Arbitrary Int64 |
Arbitrary Integer |
Arbitrary Ordering |
Arbitrary Word |
Arbitrary Word8 |
Arbitrary Word16 |
Arbitrary Word32 |
Arbitrary Word64 |
Arbitrary () |
Arbitrary OrdC |
Arbitrary OrdB |
Arbitrary OrdA |
Arbitrary C |
Arbitrary B |
Arbitrary A |
Arbitrary a => Arbitrary [a] |
(Integral a, Arbitrary a) => Arbitrary (Ratio a) |
HasResolution a => Arbitrary (Fixed a) |
(RealFloat a, Arbitrary a) => Arbitrary (Complex a) |
Arbitrary a => Arbitrary (Maybe a) |
Arbitrary a => Arbitrary (Smart a) |
Arbitrary a => Arbitrary (Shrink2 a) |
(Num a, Ord a, Arbitrary a) => Arbitrary (NonNegative a) |
(Num a, Ord a, Arbitrary a) => Arbitrary (NonZero a) |
(Num a, Ord a, Arbitrary a) => Arbitrary (Positive a) |
Arbitrary a => Arbitrary (NonEmptyList a) |
(Ord a, Arbitrary a) => Arbitrary (OrderedList a) |
Arbitrary a => Arbitrary (Fixed a) |
Arbitrary a => Arbitrary (Blind a) |
(CoArbitrary a, Arbitrary b) => Arbitrary (a -> b) |
(Arbitrary a, Arbitrary b) => Arbitrary (Either a b) |
(Arbitrary a, Arbitrary b) => Arbitrary (a, b) |
(Function a, CoArbitrary a, Arbitrary b) => Arbitrary (Fun a b) |
(Function a, CoArbitrary a, Arbitrary b) => Arbitrary ((:->) a b) |
(Arbitrary a, ShrinkState s a) => Arbitrary (Shrinking s a) |
(Arbitrary a, Arbitrary b, Arbitrary c) => Arbitrary (a, b, c) |
(Arbitrary a, Arbitrary b, Arbitrary c, Arbitrary d) => Arbitrary (a, b, c, d) |
(Arbitrary a, Arbitrary b, Arbitrary c, Arbitrary d, Arbitrary e) => Arbitrary (a, b, c, d, e) |

class CoArbitrary a where

Used for random generation of functions.

Methods

coarbitrary :: a -> Gen c -> Gen c

Used to generate a function of type `a -> c`. The implementation should use the first argument to perturb the random generator given as the second argument. the returned generator is then used to generate the function result. You can often use `variant` and `><` to implement `coarbitrary`.

Instances

CoArbitrary Bool |
CoArbitrary Char |
CoArbitrary Double |
CoArbitrary Float |
CoArbitrary Int |
CoArbitrary Int8 |
CoArbitrary Int16 |
CoArbitrary Int32 |
CoArbitrary Int64 |
CoArbitrary Integer |
CoArbitrary Ordering |
CoArbitrary Word |
CoArbitrary Word8 |
CoArbitrary Word16 |
CoArbitrary Word32 |
CoArbitrary Word64 |
CoArbitrary () |
CoArbitrary OrdC |
CoArbitrary OrdB |
CoArbitrary OrdA |
CoArbitrary C |
CoArbitrary B |
CoArbitrary A |
CoArbitrary a => CoArbitrary [a] |
(Integral a, CoArbitrary a) => CoArbitrary (Ratio a) |
HasResolution a => CoArbitrary (Fixed a) |
(RealFloat a, CoArbitrary a) => CoArbitrary (Complex a) |
CoArbitrary a => CoArbitrary (Maybe a) |
(Arbitrary a, CoArbitrary b) => CoArbitrary (a -> b) |
(CoArbitrary a, CoArbitrary b) => CoArbitrary (Either a b) |
(CoArbitrary a, CoArbitrary b) => CoArbitrary (a, b) |
(CoArbitrary a, CoArbitrary b, CoArbitrary c) => CoArbitrary (a, b, c) |
(CoArbitrary a, CoArbitrary b, CoArbitrary c, CoArbitrary d) => CoArbitrary (a, b, c, d) |
(CoArbitrary a, CoArbitrary b, CoArbitrary c, CoArbitrary d, CoArbitrary e) => CoArbitrary (a, b, c, d, e) |

## Helper functions for implementing arbitrary

arbitrarySizedIntegral :: Num a => Gen a

Generates an integral number. The number can be positive or negative and its maximum absolute value depends on the size parameter.

arbitraryBoundedIntegral :: (Bounded a, Integral a) => Gen a

Generates an integral number. The number is chosen uniformly from the entire range of the type. You may want to use `arbitrarySizedBoundedIntegral` instead.

arbitrarySizedBoundedIntegral :: (Bounded a, Integral a) => Gen a

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.

arbitrarySizedFractional :: Fractional a => Gen a

Generates a fractional number. The number can be positive or negative and its maximum absolute value depends on the size parameter.

arbitraryBoundedRandom :: (Bounded a, Random a) => Gen a

Generates an element of a bounded type. The element is chosen from the entire range of the type.

arbitraryBoundedEnum :: (Bounded a, Enum a) => Gen a

Generates an element of a bounded enumeration.

## Helper functions for implementing shrink

shrinkNothing :: a -> [a]

Returns no shrinking alternatives.

shrinkList :: (a -> [a]) -> [a] -> [[a]]

shrinkIntegral :: Integral a => a -> [a]

Shrink an integral number.

shrinkRealFrac :: RealFrac a => a -> [a]

Shrink a fraction.

## Helper functions for implementing coarbitrary

(><) :: (Gen a -> Gen a) -> (Gen a -> Gen a) -> Gen a -> Gen a

Combine two generator perturbing functions, for example the results of calls to `variant` or `coarbitrary`.

coarbitraryIntegral :: Integral a => a -> Gen b -> Gen b

A `coarbitrary` implementation for integral numbers.

coarbitraryReal :: Real a => a -> Gen b -> Gen b

A `coarbitrary` implementation for real numbers.

coarbitraryShow :: Show a => a -> Gen b -> Gen b

`coarbitrary` helper for lazy people :-).

coarbitraryEnum :: Enum a => a -> Gen b -> Gen b

A `coarbitrary` implementation for enums.

## Generators which use arbitrary

vector :: Arbitrary a => Int -> Gen [a]

Generates a list of a given length.

orderedList :: (Ord a, Arbitrary a) => Gen [a]

Generates an ordered list of a given length.