Safe Haskell | None |
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Test.QuickCheck
Contents
- quickCheck :: Testable prop => prop -> IO ()
- data Args = Args {}
- data Result
- = Success { }
- | GaveUp { }
- | Failure { }
- | NoExpectedFailure { }
- stdArgs :: Args
- quickCheckWith :: Testable prop => Args -> prop -> IO ()
- quickCheckWithResult :: Testable prop => Args -> prop -> IO Result
- quickCheckResult :: Testable prop => prop -> IO Result
- verboseCheck :: Testable prop => prop -> IO ()
- verboseCheckWith :: Testable prop => Args -> prop -> IO ()
- verboseCheckWithResult :: Testable prop => Args -> prop -> IO Result
- verboseCheckResult :: Testable prop => prop -> IO Result
- verbose :: Testable prop => prop -> Property
- data Gen a
- sized :: (Int -> Gen a) -> Gen a
- resize :: Int -> Gen a -> Gen a
- choose :: Random a => (a, a) -> Gen a
- promote :: Monad m => m (Gen a) -> Gen (m a)
- 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
- growingElements :: [a] -> Gen a
- listOf :: Gen a -> Gen [a]
- listOf1 :: Gen a -> Gen [a]
- vectorOf :: Int -> Gen a -> Gen [a]
- vector :: Arbitrary a => Int -> Gen [a]
- orderedList :: (Ord a, Arbitrary a) => Gen [a]
- sample :: Show a => Gen a -> IO ()
- sample' :: Gen a -> IO [a]
- class Arbitrary a where
- class CoArbitrary a where
- coarbitrary :: a -> Gen c -> Gen c
- arbitrarySizedIntegral :: Num a => Gen a
- arbitrarySizedFractional :: Fractional a => Gen a
- arbitrarySizedBoundedIntegral :: (Bounded a, Integral a) => Gen a
- arbitraryBoundedIntegral :: (Bounded a, Integral a) => Gen a
- arbitraryBoundedRandom :: (Bounded a, Random a) => Gen a
- arbitraryBoundedEnum :: (Bounded a, Enum a) => Gen a
- coarbitraryEnum :: Enum a => a -> Gen b -> Gen b
- shrinkNothing :: a -> [a]
- shrinkIntegral :: Integral a => a -> [a]
- shrinkRealFrac :: RealFrac a => a -> [a]
- variant :: Integral n => n -> Gen a -> Gen 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
- newtype Blind a = Blind a
- newtype Fixed a = Fixed a
- newtype OrderedList a = Ordered {
- getOrdered :: [a]
- newtype NonEmptyList a = NonEmpty {
- getNonEmpty :: [a]
- newtype Positive a = Positive {
- getPositive :: a
- newtype NonZero a = NonZero {
- getNonZero :: a
- newtype NonNegative a = NonNegative {
- getNonNegative :: a
- data Smart a = Smart Int a
- newtype Shrink2 a = Shrink2 a
- data Shrinking s a = Shrinking s a
- class ShrinkState s a where
- shrinkInit :: a -> s
- shrinkState :: a -> s -> [(a, s)]
- type Property = Gen Prop
- data Prop
- class Testable prop where
- property :: prop -> Property
- exhaustive :: prop -> Bool
- mapSize :: Testable prop => (Int -> Int) -> prop -> Property
- shrinking :: Testable prop => (a -> [a]) -> a -> (a -> prop) -> Property
- (==>) :: Testable prop => Bool -> prop -> Property
- discard :: a
- forAll :: (Show a, Testable prop) => Gen a -> (a -> prop) -> Property
- forAllShrink :: (Show a, Testable prop) => Gen a -> (a -> [a]) -> (a -> prop) -> Property
- (.&.) :: (Testable prop1, Testable prop2) => prop1 -> prop2 -> Property
- (.&&.) :: (Testable prop1, Testable prop2) => prop1 -> prop2 -> Property
- conjoin :: Testable prop => [prop] -> Property
- (.||.) :: (Testable prop1, Testable prop2) => prop1 -> prop2 -> Property
- disjoin :: Testable prop => [prop] -> Property
- whenFail :: Testable prop => IO () -> prop -> Property
- printTestCase :: Testable prop => String -> prop -> Property
- whenFail' :: Testable prop => IO () -> prop -> Property
- expectFailure :: Testable prop => prop -> Property
- within :: Testable prop => Int -> prop -> Property
- label :: Testable prop => String -> prop -> Property
- collect :: (Show a, Testable prop) => a -> prop -> Property
- classify :: Testable prop => Bool -> String -> prop -> Property
- cover :: Testable prop => Bool -> Int -> String -> prop -> Property
- once :: Testable prop => prop -> Property
- newtype Str = MkStr String
- ranges :: (Show a, Integral a) => a -> a -> Str
Running tests
quickCheck :: Testable prop => prop -> IO ()
Tests a property and prints the results to stdout
.
data Args
Args specifies arguments to the QuickCheck driver
Constructors
Args | |
Fields
|
data Result
Result represents the test result
Constructors
Success | |
Fields
| |
GaveUp | |
Fields
| |
Failure | |
Fields
| |
NoExpectedFailure | |
Fields
|
quickCheckWith :: Testable prop => Args -> prop -> IO ()
Tests a property, using test arguments, and prints the results to stdout
.
quickCheckWithResult :: Testable prop => Args -> prop -> IO Result
Tests a property, using test arguments, produces a test result, and prints the results to stdout
.
quickCheckResult :: Testable prop => prop -> IO Result
Tests a property, produces a test result, and prints the results to stdout
.
Running tests verbosely
verboseCheck :: Testable prop => prop -> IO ()
Tests a property and prints the results and all test cases generated to stdout
.
This is just a convenience function that means the same as quickCheck
.
verbose
.
verboseCheckWith :: Testable prop => Args -> prop -> IO ()
Tests a property, using test arguments, and prints the results and all test cases generated to stdout
.
This is just a convenience function that combines quickCheckWith
and verbose
.
verboseCheckWithResult :: Testable prop => Args -> prop -> IO Result
Tests a property, using test arguments, produces a test result, and prints the results and all test cases generated to stdout
.
This is just a convenience function that combines quickCheckWithResult
and verbose
.
verboseCheckResult :: Testable prop => prop -> IO Result
Tests a property, produces a test result, and prints the results and all test cases generated to stdout
.
This is just a convenience function that combines quickCheckResult
and verbose
.
verbose :: Testable prop => prop -> Property
Prints out the generated testcase every time the property is tested,
like verboseCheck
from QuickCheck 1.
Only variables quantified over inside the verbose
are printed.
Random generation
Generator combinators
resize :: Int -> Gen a -> Gen a
Overrides the size parameter. Returns a generator which uses the given size instead of the runtime-size parameter.
promote :: Monad m => m (Gen a) -> Gen (m a)
Promotes a monadic generator to a generator of monadic values.
suchThatMaybe :: Gen a -> (a -> Bool) -> Gen (Maybe a)
Tries to generate a value that satisfies a predicate.
Randomly uses one of the given generators. The input list must be non-empty.
frequency :: [(Int, Gen a)] -> Gen a
Chooses one of the given generators, with a weighted random distribution. The input list must be non-empty.
growingElements :: [a] -> Gen a
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.
Generates a list of random length. The maximum length depends on the size parameter.
Generates a non-empty list of random length. The maximum length depends on the size parameter.
Generators which use Arbitrary
orderedList :: (Ord a, Arbitrary a) => Gen [a]
Generates an ordered list of a given length.
Generator debugging
Arbitrary and CoArbitrary classes
class Arbitrary a where
Random generation and shrinking of values.
Methods
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
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
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.
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.
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.
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.
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.
coarbitraryEnum :: Enum a => a -> Gen b -> Gen b
A coarbitrary
implementation for enums.
Helper functions for implementing shrink
shrinkNothing :: a -> [a]
Returns no shrinking alternatives.
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 :-).
Type-level modifiers for changing generator behavior
newtype OrderedList a
Ordered xs
: guarantees that xs is ordered.
Constructors
Ordered | |
Fields
|
Instances
Eq a => Eq (OrderedList a) | |
Ord a => Ord (OrderedList a) | |
Read a => Read (OrderedList a) | |
Show a => Show (OrderedList a) | |
(Ord a, Arbitrary a) => Arbitrary (OrderedList a) |
newtype NonEmptyList a
NonEmpty xs
: guarantees that xs is non-empty.
Constructors
NonEmpty | |
Fields
|
Instances
Eq a => Eq (NonEmptyList a) | |
Ord a => Ord (NonEmptyList a) | |
Read a => Read (NonEmptyList a) | |
Show a => Show (NonEmptyList a) | |
Arbitrary a => Arbitrary (NonEmptyList a) |
newtype NonNegative a
NonNegative x
: guarantees that x >= 0
.
Constructors
NonNegative | |
Fields
|
Instances
Enum a => Enum (NonNegative a) | |
Eq a => Eq (NonNegative a) | |
Integral a => Integral (NonNegative a) | |
Num a => Num (NonNegative a) | |
Ord a => Ord (NonNegative a) | |
Read a => Read (NonNegative a) | |
Real a => Real (NonNegative a) | |
Show a => Show (NonNegative a) | |
(Num a, Ord a, Arbitrary a) => Arbitrary (NonNegative a) |
data Smart a
Smart _ x
: tries a different order when shrinking.
newtype Shrink2 a
Shrink2 x
: allows 2 shrinking steps at the same time when shrinking x
Constructors
Shrink2 a |
data Shrinking s a
Shrinking _ x
: allows for maintaining a state during shrinking.
Constructors
Shrinking s a |
class ShrinkState s a where
Properties
class Testable prop where
The class of things which can be tested, i.e. turned into a property.
Property combinators
mapSize :: Testable prop => (Int -> Int) -> prop -> Property
Changes the maximum test case size for a property.
Arguments
:: Testable prop | |
=> (a -> [a]) |
|
-> a | The original argument |
-> (a -> prop) | |
-> Property |
Shrinks the argument to property if it fails. Shrinking is done automatically for most types. This is only needed when you want to override the default behavior.
(==>) :: Testable prop => Bool -> prop -> Property
Implication for properties: The resulting property holds if
the first argument is False
(in which case the test case is discarded),
or if the given property holds.
discard :: a
A special exception that makes QuickCheck discard the test case.
Normally you should use ==>
, but if for some reason this isn't
possible (e.g. you are deep inside a generator), use discard
instead.
forAll :: (Show a, Testable prop) => Gen a -> (a -> prop) -> Property
Explicit universal quantification: uses an explicitly given test case generator.
forAllShrink :: (Show a, Testable prop) => Gen a -> (a -> [a]) -> (a -> prop) -> Property
Like forAll
, but tries to shrink the argument for failing test cases.
Experimental combinators for conjunction and disjunction
(.&.) :: (Testable prop1, Testable prop2) => prop1 -> prop2 -> Property
Nondeterministic choice: p1
.&.
p2
picks randomly one of
p1
and p2
to test. If you test the property 100 times it
makes 100 random choices.
(.&&.) :: (Testable prop1, Testable prop2) => prop1 -> prop2 -> Property
Conjunction: p1
.&&.
p2
passes if both p1
and p2
pass.
(.||.) :: (Testable prop1, Testable prop2) => prop1 -> prop2 -> Property
Disjunction: p1
.||.
p2
passes unless p1
and p2
simultaneously fail.
Handling failure
whenFail :: Testable prop => IO () -> prop -> Property
Performs an IO
action after the last failure of a property.
printTestCase :: Testable prop => String -> prop -> Property
Prints a message to the terminal as part of the counterexample.
whenFail' :: Testable prop => IO () -> prop -> Property
Performs an IO
action every time a property fails. Thus,
if shrinking is done, this can be used to keep track of the
failures along the way.
expectFailure :: Testable prop => prop -> Property
Modifies a property so that it is expected to fail for some test cases.
within :: Testable prop => Int -> prop -> Property
Considers a property failed if it does not complete within the given number of microseconds.
Test distribution
label :: Testable prop => String -> prop -> Property
Attaches a label to a property. This is used for reporting test case distribution.
collect :: (Show a, Testable prop) => a -> prop -> Property
Labels a property with a value:
collect x = label (show x)
Arguments
:: Testable prop | |
=> Bool |
|
-> String | Label. |
-> prop | |
-> Property |
Conditionally labels test case.
Arguments
:: Testable prop | |
=> Bool |
|
-> Int | The required percentage (0-100) of test cases. |
-> String | Label for the test case class. |
-> prop | |
-> Property |
Checks that at least the given proportion of the test cases belong to the given class.