 | QuickCheck-2.1.1.1: Automatic testing of Haskell programs | Contents | Index |
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Synopsis |
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Running tests
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quickCheck :: Testable prop => prop -> IO () |
Tests a property and prints the results to stdout.
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data Args |
Args specifies arguments to the QuickCheck driver
| Constructors | Args | | replay :: Maybe (StdGen, Int) | should we replay a previous test?
| maxSuccess :: Int | maximum number of successful tests before succeeding
| maxDiscard :: Int | maximum number of discarded tests before giving up
| maxSize :: Int | size to use for the biggest test cases
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data Result |
Result represents the test result
| Constructors | Success | | labels :: [(String, Int)] | labels and frequencies found during all tests
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| GaveUp | | numTests :: Int | number of successful tests performed
| labels :: [(String, Int)] | labels and frequencies found during all tests
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| Failure | | usedSeed :: StdGen | what seed was used
| usedSize :: Int | what was the test size
| reason :: String | what was the reason
| labels :: [(String, Int)] | labels and frequencies found during all tests
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| NoExpectedFailure | | labels :: [(String, Int)] | labels and frequencies found during all tests
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stdArgs :: Args |
stdArgs are the default test arguments used
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quickCheckWith :: Testable prop => Args -> prop -> IO () |
Tests a property, using test arguments, and prints the results to stdout.
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quickCheckWithResult :: Testable prop => Args -> prop -> IO Result |
Tests a property, using test arguments, produces a test result, and prints the results to stdout.
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quickCheckResult :: Testable prop => prop -> IO Result |
Tests a property, produces a test result, and prints the results to stdout.
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Random generation
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data Gen a |
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Generator combinators
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sized :: (Int -> Gen a) -> Gen a |
Used to construct generators that depend on the size parameter.
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resize :: Int -> Gen a -> Gen a |
Overrides the size parameter. Returns a generator which uses
the given size instead of the runtime-size parameter.
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choose :: Random a => (a, a) -> Gen a |
Generates a random element in the given inclusive range.
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promote :: Monad m => m (Gen a) -> Gen (m a) |
Promotes a generator to a generator of monadic values.
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suchThat :: Gen a -> (a -> Bool) -> Gen a |
Generates a value that satisfies a predicate.
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suchThatMaybe :: Gen a -> (a -> Bool) -> Gen (Maybe a) |
Tries to generate a value that satisfies a predicate.
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oneof :: [Gen a] -> Gen a |
Randomly uses one of the given generators. The input list
must be non-empty.
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frequency :: [(Int, Gen a)] -> Gen a |
Chooses one of the given generators, with a weighted random distribution.
The input list must be non-empty.
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elements :: [a] -> Gen a |
Generates one of the given values. The input list must be non-empty.
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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.
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listOf :: Gen a -> Gen [a] |
Generates a list of random length. The maximum length depends on the
size parameter.
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listOf1 :: Gen a -> Gen [a] |
Generates a non-empty list of random length. The maximum length
depends on the size parameter.
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vectorOf :: Int -> Gen a -> Gen [a] |
Generates a list of the given length.
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Generators which use Arbitrary
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vector :: Arbitrary a => Int -> Gen [a] |
Generates a list of a given length.
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orderedList :: (Ord a, Arbitrary a) => Gen [a] |
Generates an ordered list of a given length.
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Generator debugging
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sample :: Show a => Gen a -> IO () |
Generates some example values and prints them to stdout.
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sample' :: Gen a -> IO [a] |
Generates some example values.
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Arbitrary and CoArbitrary classes.
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class Arbitrary a where |
Random generation and shrinking of values.
| | 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.
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| | Instances | Arbitrary Bool | Arbitrary Char | Arbitrary Double | Arbitrary Float | Arbitrary Int | Arbitrary Integer | Arbitrary () | Arbitrary OrdC | Arbitrary OrdB | Arbitrary OrdA | Arbitrary C | Arbitrary B | Arbitrary A | Arbitrary a => Arbitrary [a] | (Integral a, Arbitrary a) => Arbitrary (Ratio a) | Arbitrary a => Arbitrary (Maybe a) | (RealFloat a, Arbitrary a) => Arbitrary (Complex 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) | (Arbitrary a, ShrinkState s a) => Arbitrary (Shrinking s a) | (FunArbitrary a, Arbitrary b) => Arbitrary (Fun a b) | (FunArbitrary a, Arbitrary c) => Arbitrary (:-> a c) | (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) |
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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.
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| | Instances | CoArbitrary Bool | CoArbitrary Char | CoArbitrary Double | CoArbitrary Float | CoArbitrary Int | CoArbitrary Integer | CoArbitrary () | CoArbitrary OrdC | CoArbitrary OrdB | CoArbitrary OrdA | CoArbitrary C | CoArbitrary B | CoArbitrary A | CoArbitrary a => CoArbitrary [a] | (Integral a, CoArbitrary a) => CoArbitrary (Ratio a) | CoArbitrary a => CoArbitrary (Maybe a) | (RealFloat a, CoArbitrary a) => CoArbitrary (Complex 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) |
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Helper functions for implementing arbitrary
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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.
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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.
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arbitraryBoundedIntegral :: (Bounded a, Integral a) => Gen a |
Generates an integral number. The number is chosen from the entire
range of the type.
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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.
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Helper functions for implementing shrink
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shrinkNothing :: a -> [a] |
Returns no shrinking alternatives.
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shrinkIntegral :: Integral a => a -> [a] |
Shrink an integral number.
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shrinkRealFrac :: RealFrac a => a -> [a] |
Shrink a fraction.
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Helper functions for implementing coarbitrary
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variant :: Integral n => n -> Gen a -> Gen a |
Modifies a generator using an integer seed.
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(><) :: (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.
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coarbitraryIntegral :: Integral a => a -> Gen b -> Gen b |
A coarbitrary implementation for integral numbers.
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coarbitraryReal :: Real a => a -> Gen b -> Gen b |
A coarbitrary implementation for real numbers.
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coarbitraryShow :: Show a => a -> Gen b -> Gen b |
coarbitrary helper for lazy people :-).
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Type-level modifiers for changing generator behavior
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newtype Blind a |
Blind x: as x, but x does not have to be in the Show class.
| Constructors | | Instances | |
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newtype Fixed a |
Fixed x: as x, but will not be shrunk.
| Constructors | | Instances | |
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newtype OrderedList a |
Ordered xs: guarantees that xs is ordered.
| Constructors | | Instances | |
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newtype NonEmptyList a |
NonEmpty xs: guarantees that xs is non-empty.
| Constructors | | Instances | |
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newtype Positive a |
Positive x: guarantees that x > 0.
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newtype NonZero a |
NonZero x: guarantees that x /= 0.
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newtype NonNegative a |
NonNegative x: guarantees that x >= 0.
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data Smart a |
Smart _ x: tries a different order when shrinking.
| Constructors | | Instances | |
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newtype Shrink2 a |
Shrink2 x: allows 2 shrinking steps at the same time when shrinking x
| Constructors | | Instances | |
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data Shrinking s a |
Shrinking _ x: allows for maintaining a state during shrinking.
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class ShrinkState s a where |
| Methods | shrinkInit :: a -> s | | shrinkState :: a -> s -> [(a, s)] |
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Properties
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type Property = Gen Prop |
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data Prop |
Instances | |
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class Testable prop where |
The class of things which can be tested, i.e. turned into a property.
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Property combinators
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mapSize :: Testable prop => (Int -> Int) -> prop -> Property |
Changes the maximum test case size for a property.
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shrinking |
:: Testable prop | | => a -> [a] | shrink-like function.
| -> 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 weh you want to
override the default behavior.
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(==>) :: Testable prop => Bool -> prop -> Property |
Implication for properties: The resulting property holds if
the first argument is False, or if the given property holds.
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forAll :: (Show a, Testable prop) => Gen a -> (a -> prop) -> Property |
Explicit universal quantification: uses an explicitly given
test case generator.
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forAllShrink :: (Show a, Testable prop) => Gen a -> (a -> [a]) -> (a -> prop) -> Property |
Like forAll, but tries to shrink the argument for failing test cases.
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(.&.) :: (Testable prop1, Testable prop2) => prop1 -> prop2 -> Property |
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Handling failure
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whenFail :: Testable prop => IO () -> prop -> Property |
Performs an IO action after the last failure of a property.
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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.
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expectFailure :: Testable prop => prop -> Property |
Modifies a property so that it is expected to fail for some test cases.
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within :: Testable prop => Int -> prop -> Property |
Considers a property failed if it does not complete within
the given number of microseconds.
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Test distribution
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label :: Testable prop => String -> prop -> Property |
Attaches a label to a property. This is used for reporting
test case distribution.
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collect :: (Show a, Testable prop) => a -> prop -> Property |
Labels a property with a value:
collect x = label (show x)
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classify |
:: Testable prop | | => Bool | True if the test case should be labelled.
| -> String | Label.
| -> prop | | -> Property | | Conditionally labels test case.
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cover |
:: Testable prop | | => Bool | True if the test case belongs to the class.
| -> 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.
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Text formatting
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newtype Str |
Constructors | | Instances | |
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ranges :: Integral a => a -> a -> Str |
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