Safe Haskell | Safe-Inferred |
---|---|
Language | Haskell98 |
Test case generation.
- newtype Gen a = MkGen {}
- variant :: Integral n => n -> Gen a -> Gen a
- sized :: (Int -> Gen a) -> Gen a
- resize :: Int -> Gen a -> Gen a
- scale :: (Int -> Int) -> Gen a -> Gen a
- choose :: Random a => (a, a) -> Gen a
- generate :: Gen a -> IO a
- sample' :: Gen a -> IO [a]
- sample :: Show a => Gen a -> IO ()
- suchThat :: Gen a -> (a -> Bool) -> Gen a
- suchThatMaybe :: Gen a -> (a -> Bool) -> Gen (Maybe a)
- oneof :: [Gen a] -> Gen a
- frequency :: [(Int, Gen a)] -> Gen a
- elements :: [a] -> Gen a
- sublistOf :: [a] -> Gen [a]
- shuffle :: [a] -> Gen [a]
- growingElements :: [a] -> Gen a
- listOf :: Gen a -> Gen [a]
- listOf1 :: Gen a -> Gen [a]
- vectorOf :: Int -> Gen a -> Gen [a]
- infiniteListOf :: Gen a -> Gen [a]
Generator type
A generator for values of type a
.
Primitive generator combinators
sized :: (Int -> Gen a) -> Gen a Source
Used to construct generators that depend on the size parameter.
resize :: Int -> Gen a -> Gen a Source
Overrides the size parameter. Returns a generator which uses the given size instead of the runtime-size parameter.
scale :: (Int -> Int) -> Gen a -> Gen a Source
Adjust the size parameter, by transforming it with the given function.
choose :: Random a => (a, a) -> Gen a Source
Generates a random element in the given inclusive range.
generate :: Gen a -> IO a Source
Run a generator. The size passed to the generator is always 30;
if you want another size then you should explicitly use resize
.
Common generator combinators
suchThatMaybe :: Gen a -> (a -> Bool) -> Gen (Maybe a) Source
Tries to generate a value that satisfies a predicate.
oneof :: [Gen a] -> Gen a Source
Randomly uses one of the given generators. The input list must be non-empty.
frequency :: [(Int, Gen a)] -> Gen a Source
Chooses one of the given generators, with a weighted random distribution. The input list must be non-empty.
growingElements :: [a] -> Gen a Source
Takes a list of elements of increasing size, and chooses among an initial segment of the list. The size of this initial segment increases with the size parameter. The input list must be non-empty.
listOf :: Gen a -> Gen [a] Source
Generates a list of random length. The maximum length depends on the size parameter.
listOf1 :: Gen a -> Gen [a] Source
Generates a non-empty list of random length. The maximum length depends on the size parameter.
infiniteListOf :: Gen a -> Gen [a] Source
Generates an infinite list.