Safe Haskell | None |
---|---|
Language | Haskell2010 |
GenValidity
exists to make tests involving Validity
types easier and speed
up the generation of data for them.
Let's use the example from Data.Validity
again: A datatype that represents
primes.
To implement tests for this datatype, we would have to be able to generate
both primes and non-primes. We could do this with
(Prime $ arbitrary)
but this is tedious and inefficient.suchThat
isValid
The GenValid
type class allows you to specify how to (efficiently)
generate valid data of the given type to allow for easier and quicker testing.
Just instantiating GenUnchecked
already gives you access to a default instance
of GenValid
and GenInvalid
but writing custom implementations of these functions
may speed up the generation of data.
For example, to generate primes, we don't have to consider even numbers other than 2. A more efficient implementation could then look as follows:
instance GenUnchecked Prime where genUnchecked = Prime <$> arbitrary
instance GenValid Prime where genValid = Prime <$> (oneof [ pure 2 , ((\y -> 2 * abs y + 1) <$> arbitrary) `suchThat` isPrime) ])
Typical examples of tests involving validity could look as follows:
it "succeeds when given valid input" $ do forAllValid $ \input -> myFunction input `shouldSatisfy` isRight
it "produces valid output when it succeeds" $ do forAllUnchecked $ \input -> case myFunction input of Nothing -> return () -- Can happen Just output -> output `shouldSatisfy` isValid
Synopsis
- module Data.Validity
- class GUncheckedSubtermsIncl f a where
- class GUncheckedSubterms f a where
- class GUncheckedRecursivelyShrink f where
- class GGenUnchecked f where
- class (Validity a, GenUnchecked a) => GenInvalid a where
- class (Validity a, GenUnchecked a) => GenValid a where
- class GenUnchecked a where
- shrinkT2 :: (a -> [a]) -> (a, a) -> [(a, a)]
- shrinkT3 :: (a -> [a]) -> (a, a, a) -> [(a, a, a)]
- upTo :: Int -> Gen Int
- genSplit :: Int -> Gen (Int, Int)
- genSplit3 :: Int -> Gen (Int, Int, Int)
- genSplit4 :: Int -> Gen (Int, Int, Int, Int)
- genSplit5 :: Int -> Gen (Int, Int, Int, Int, Int)
- arbPartition :: Int -> Gen [Int]
- genListOf :: Gen a -> Gen [a]
- gShrinkUnchecked :: (Generic a, GUncheckedRecursivelyShrink (Rep a), GUncheckedSubterms (Rep a) a) => a -> [a]
- uncheckedRecursivelyShrink :: (Generic a, GUncheckedRecursivelyShrink (Rep a)) => a -> [a]
- uncheckedSubterms :: (Generic a, GUncheckedSubterms (Rep a) a) => a -> [a]
Documentation
module Data.Validity
class GUncheckedSubtermsIncl f a where Source #
gUncheckedSubtermsIncl :: f a -> [a] Source #
Instances
class GUncheckedSubterms f a where Source #
gUncheckedSubterms :: f a -> [a] Source #
Instances
GUncheckedSubterms (V1 :: * -> *) a Source # | |
Defined in Data.GenValidity gUncheckedSubterms :: V1 a -> [a] Source # | |
GUncheckedSubterms (U1 :: * -> *) a Source # | |
Defined in Data.GenValidity gUncheckedSubterms :: U1 a -> [a] Source # | |
GUncheckedSubterms (K1 i a :: * -> *) b Source # | |
Defined in Data.GenValidity gUncheckedSubterms :: K1 i a b -> [b] Source # | |
(GUncheckedSubtermsIncl f a, GUncheckedSubtermsIncl g a) => GUncheckedSubterms (f :+: g) a Source # | |
Defined in Data.GenValidity gUncheckedSubterms :: (f :+: g) a -> [a] Source # | |
(GUncheckedSubtermsIncl f a, GUncheckedSubtermsIncl g a) => GUncheckedSubterms (f :*: g) a Source # | |
Defined in Data.GenValidity gUncheckedSubterms :: (f :*: g) a -> [a] Source # | |
GUncheckedSubterms f a => GUncheckedSubterms (M1 i c f) a Source # | |
Defined in Data.GenValidity gUncheckedSubterms :: M1 i c f a -> [a] Source # |
class GUncheckedRecursivelyShrink f where Source #
gUncheckedRecursivelyShrink :: f a -> [f a] Source #
Instances
class GGenUnchecked f where Source #
gGenUnchecked :: Gen (f a) Source #
Instances
GGenUnchecked (U1 :: * -> *) Source # | |
Defined in Data.GenValidity gGenUnchecked :: Gen (U1 a) Source # | |
GenUnchecked a => GGenUnchecked (K1 i a :: * -> *) Source # | |
Defined in Data.GenValidity gGenUnchecked :: Gen (K1 i a a0) Source # | |
(GGenUnchecked a, GGenUnchecked b) => GGenUnchecked (a :+: b) Source # | |
Defined in Data.GenValidity gGenUnchecked :: Gen ((a :+: b) a0) Source # | |
(GGenUnchecked a, GGenUnchecked b) => GGenUnchecked (a :*: b) Source # | |
Defined in Data.GenValidity gGenUnchecked :: Gen ((a :*: b) a0) Source # | |
GGenUnchecked a => GGenUnchecked (M1 i c a) Source # | |
Defined in Data.GenValidity gGenUnchecked :: Gen (M1 i c a a0) Source # |
class (Validity a, GenUnchecked a) => GenInvalid a where Source #
A class of types for which invalid values can be generated.
genInvalid :: Gen a Source #
shrinkInvalid :: a -> [a] Source #
Instances
GenInvalid Double Source # | Either |
Defined in Data.GenValidity genInvalid :: Gen Double Source # shrinkInvalid :: Double -> [Double] Source # | |
GenInvalid Float Source # | Either |
Defined in Data.GenValidity genInvalid :: Gen Float Source # shrinkInvalid :: Float -> [Float] Source # | |
GenInvalid a => GenInvalid [a] Source # | This instance ensures that the generated list contains at least one element
that satisfies |
Defined in Data.GenValidity genInvalid :: Gen [a] Source # shrinkInvalid :: [a] -> [[a]] Source # | |
GenInvalid a => GenInvalid (Maybe a) Source # | |
Defined in Data.GenValidity genInvalid :: Gen (Maybe a) Source # shrinkInvalid :: Maybe a -> [Maybe a] Source # | |
(Integral a, Num a, Ord a, GenValid a) => GenInvalid (Ratio a) Source # | |
Defined in Data.GenValidity genInvalid :: Gen (Ratio a) Source # shrinkInvalid :: Ratio a -> [Ratio a] Source # | |
GenInvalid a => GenInvalid (NonEmpty a) Source # | |
Defined in Data.GenValidity genInvalid :: Gen (NonEmpty a) Source # shrinkInvalid :: NonEmpty a -> [NonEmpty a] Source # | |
(GenInvalid a, GenInvalid b) => GenInvalid (Either a b) Source # | This instance ensures that the generated tupse contains at least one invalid element. The other element is unchecked. |
Defined in Data.GenValidity genInvalid :: Gen (Either a b) Source # shrinkInvalid :: Either a b -> [Either a b] Source # | |
(GenInvalid a, GenInvalid b) => GenInvalid (a, b) Source # | |
Defined in Data.GenValidity genInvalid :: Gen (a, b) Source # shrinkInvalid :: (a, b) -> [(a, b)] Source # | |
(GenInvalid a, GenInvalid b, GenInvalid c) => GenInvalid (a, b, c) Source # | This instance ensures that the generated triple contains at least one invalid element. The other two are unchecked. |
Defined in Data.GenValidity genInvalid :: Gen (a, b, c) Source # shrinkInvalid :: (a, b, c) -> [(a, b, c)] Source # | |
(GenInvalid a, GenInvalid b, GenInvalid c, GenInvalid d) => GenInvalid (a, b, c, d) Source # | This instance ensures that the generated triple contains at least one invalid element. The other two are unchecked. |
Defined in Data.GenValidity genInvalid :: Gen (a, b, c, d) Source # shrinkInvalid :: (a, b, c, d) -> [(a, b, c, d)] Source # | |
(GenInvalid a, GenInvalid b, GenInvalid c, GenInvalid d, GenInvalid e) => GenInvalid (a, b, c, d, e) Source # | This instance ensures that the generated triple contains at least one invalid element. The other two are unchecked. |
Defined in Data.GenValidity genInvalid :: Gen (a, b, c, d, e) Source # shrinkInvalid :: (a, b, c, d, e) -> [(a, b, c, d, e)] Source # |
class (Validity a, GenUnchecked a) => GenValid a where Source #
A class of types for which valid values can be generated.
If you also write Arbitrary
instances for GenValid
types, it may be
best to simply write arbitrary = genValid
.
Instances
class GenUnchecked a where Source #
A class of types for which truly arbitrary values can be generated.
Automatic instances with Generic
An instance of this class can be made automatically if the type in question
has a Generic
instance. This instance will try to use genUnchecked
to
generate all structural sub-parts of the value that is being generated.
Example:
{-# LANGUAGE DeriveGeneric #-} data MyType = MyType Double String deriving (Show, Eq, Generic) instance GenUnchecked MyType
generates something like:
instance GenUnchecked MyType where genUnchecked = MyType <$> genUnchecked <*> genUnchecked
genUnchecked :: Gen a Source #
genUnchecked :: (Generic a, GGenUnchecked (Rep a)) => Gen a Source #
shrinkUnchecked :: a -> [a] Source #
shrinkUnchecked :: (Generic a, GUncheckedRecursivelyShrink (Rep a), GUncheckedSubterms (Rep a) a) => a -> [a] Source #
Instances
genSplit :: Int -> Gen (Int, Int) Source #
'genSplit a' generates a tuple '(b, c)' such that 'b + c' equals a
.
genSplit3 :: Int -> Gen (Int, Int, Int) Source #
'genSplit3 a' generates a triple '(b, c, d)' such that 'b + c + d' equals a
.
genSplit4 :: Int -> Gen (Int, Int, Int, Int) Source #
'genSplit4 a' generates a quadruple '(b, c, d, e)' such that 'b + c + d + e' equals a
.
genSplit5 :: Int -> Gen (Int, Int, Int, Int, Int) Source #
'genSplit5 a' generates a quadruple '(b, c, d, e, f)' such that 'b + c + d + e + f' equals a
.
arbPartition :: Int -> Gen [Int] Source #
'arbPartition n' generates a list ls
such that 'sum ls' equals n
.
genListOf :: Gen a -> Gen [a] Source #
A version of listOf
that takes size into account more accurately.
gShrinkUnchecked :: (Generic a, GUncheckedRecursivelyShrink (Rep a), GUncheckedSubterms (Rep a) a) => a -> [a] Source #
Shrink a term to any of its immediate subterms, and also recursively shrink all subterms.
uncheckedRecursivelyShrink :: (Generic a, GUncheckedRecursivelyShrink (Rep a)) => a -> [a] Source #
Recursively shrink all immediate uncheckedSubterms.
uncheckedSubterms :: (Generic a, GUncheckedSubterms (Rep a) a) => a -> [a] Source #
All immediate uncheckedSubterms of a term.