| Safe Haskell | Safe |
|---|---|
| Language | Haskell98 |
Test.QuickCheck.Property
Contents
Description
Combinators for constructing properties.
- newtype Property = MkProperty {
- unProperty :: Gen Prop
- class Testable prop where
- data Discard = Discard
- morallyDubiousIOProperty :: Testable prop => IO prop -> Property
- ioProperty :: Testable prop => IO prop -> Property
- protect :: (AnException -> a) -> IO a -> IO a
- newtype Prop = MkProp {}
- data Rose a
- ioRose :: IO (Rose Result) -> Rose Result
- joinRose :: Rose (Rose a) -> Rose a
- reduceRose :: Rose Result -> IO (Rose Result)
- onRose :: (a -> [Rose a] -> Rose a) -> Rose a -> Rose a
- protectRose :: IO (Rose Result) -> IO (Rose Result)
- protectResults :: Rose Result -> Rose Result
- data Callback
- = PostTest CallbackKind (State -> Result -> IO ())
- | PostFinalFailure CallbackKind (State -> Result -> IO ())
- data CallbackKind
- data Result = MkResult {}
- exception :: String -> AnException -> Result
- formatException :: String -> AnException -> String
- protectResult :: IO Result -> IO Result
- succeeded :: Result
- failed :: Result
- rejected :: Result
- liftBool :: Bool -> Result
- mapResult :: Testable prop => (Result -> Result) -> prop -> Property
- mapTotalResult :: Testable prop => (Result -> Result) -> prop -> Property
- mapRoseResult :: Testable prop => (Rose Result -> Rose Result) -> prop -> Property
- mapProp :: Testable prop => (Prop -> Prop) -> prop -> Property
- mapSize :: Testable prop => (Int -> Int) -> prop -> Property
- shrinking :: Testable prop => (a -> [a]) -> a -> (a -> prop) -> Property
- noShrinking :: Testable prop => prop -> Property
- callback :: Testable prop => Callback -> prop -> Property
- counterexample :: Testable prop => String -> prop -> Property
- showCounterexample :: String -> IO String
- printTestCase :: Testable prop => String -> prop -> Property
- whenFail :: Testable prop => IO () -> prop -> Property
- whenFail' :: Testable prop => IO () -> prop -> Property
- verbose :: Testable prop => prop -> Property
- expectFailure :: Testable prop => prop -> Property
- once :: Testable prop => prop -> Property
- again :: Testable prop => prop -> Property
- withMaxSuccess :: 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
- (==>) :: Testable prop => Bool -> prop -> Property
- within :: Testable prop => Int -> prop -> Property
- 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
- (===) :: (Eq a, Show a) => a -> a -> Property
- total :: NFData a => a -> Property
Property and Testable types
The type of properties.
Constructors
| MkProperty | |
Fields
| |
class Testable prop where Source #
The class of properties, i.e., types which QuickCheck knows how to test.
Typically a property will be a function returning Bool or Property.
If a property does no quantification, i.e. has no
parameters and doesn't use forAll, it will only be tested once.
This may not be what you want if your property is an IO Bool.
You can change this behaviour using the again combinator.
Minimal complete definition
If a property returns Discard, the current test case is discarded,
the same as if a precondition was false.
Constructors
| Discard |
morallyDubiousIOProperty :: Testable prop => IO prop -> Property Source #
Deprecated: Use ioProperty instead
Do I/O inside a property.
ioProperty :: Testable prop => IO prop -> Property Source #
Do I/O inside a property.
Warning: any random values generated inside of the argument to ioProperty
will not currently be shrunk. For best results, generate all random values
before calling ioProperty.
Exception handling
Type Prop
type Rose
reduceRose :: Rose Result -> IO (Rose Result) Source #
Execute the IORose bits of a rose tree, returning a tree constructed by MkRose.
onRose :: (a -> [Rose a] -> Rose a) -> Rose a -> Rose a Source #
Apply a function to the outermost MkRose constructor of a rose tree. The function must be total!
protectRose :: IO (Rose Result) -> IO (Rose Result) Source #
Wrap a rose tree in an exception handler.
protectResults :: Rose Result -> Rose Result Source #
Wrap all the Results in a rose tree in exception handlers.
Result type
Different kinds of callbacks
Constructors
| PostTest CallbackKind (State -> Result -> IO ()) | Called just after a test |
| PostFinalFailure CallbackKind (State -> Result -> IO ()) | Called with the final failing test-case |
data CallbackKind Source #
Constructors
| Counterexample | Affected by the |
| NotCounterexample | Not affected by the |
The result of a single test.
Constructors
| MkResult | |
Fields
| |
formatException :: String -> AnException -> String Source #
Lifting and mapping functions
Property combinators
mapSize :: Testable prop => (Int -> Int) -> prop -> Property Source #
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 a property if it fails. Shrinking is done automatically for most types. This function is only needed when you want to override the default behavior.
noShrinking :: Testable prop => prop -> Property Source #
Disables shrinking for a property altogether.
counterexample :: Testable prop => String -> prop -> Property Source #
Adds the given string to the counterexample if the property fails.
printTestCase :: Testable prop => String -> prop -> Property Source #
Deprecated: Use counterexample instead
Adds the given string to the counterexample if the property fails.
whenFail :: Testable prop => IO () -> prop -> Property Source #
Performs an IO action after the last failure of a property.
whenFail' :: Testable prop => IO () -> prop -> Property Source #
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.
verbose :: Testable prop => prop -> Property Source #
Prints out the generated testcase every time the property is tested.
Only variables quantified over inside the verbose are printed.
expectFailure :: Testable prop => prop -> Property Source #
Indicates that a property is supposed to fail. QuickCheck will report an error if it does not fail.
once :: Testable prop => prop -> Property Source #
Modifies a property so that it only will be tested once.
Opposite of again.
again :: Testable prop => prop -> Property Source #
Modifies a property so that it will be tested repeatedly.
Opposite of once.
withMaxSuccess :: Testable prop => Int -> prop -> Property Source #
Configures how many times a property will be tested.
For example,
quickCheck (withMaxSuccess 1000 p)
will test p up to 1000 times.
label :: Testable prop => String -> prop -> Property Source #
Attaches a label to a property. This is used for reporting test case distribution.
For example:
prop_reverse_reverse :: [Int] -> Property
prop_reverse_reverse xs =
label ("length of input is " ++ show (length xs)) $
reverse (reverse xs) === xs>>>quickCheck prop_reverse_reverse+++ OK, passed 100 tests: 7% length of input is 7 6% length of input is 3 5% length of input is 4 4% length of input is 6 ...
collect :: (Show a, Testable prop) => a -> prop -> Property Source #
Attaches a label to a property. This is used for reporting test case distribution.
collect x = label (show x)
For example:
prop_reverse_reverse :: [Int] -> Property
prop_reverse_reverse xs =
collect (length xs) $
reverse (reverse xs) === xs>>>quickCheck prop_reverse_reverse+++ OK, passed 100 tests: 7% 7 6% 3 5% 4 4% 6 ...
Arguments
| :: Testable prop | |
| => Bool |
|
| -> String | Label. |
| -> prop | |
| -> Property |
Records how many test cases satisfy a given condition.
For example:
prop_sorted_sort :: [Int] -> Property prop_sorted_sort xs = sorted xs ==> classify (length xs > 1) "non-trivial" $ sort xs === xs
>>>quickCheck prop_sorted_sort+++ OK, passed 100 tests (22% non-trivial).
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 successful test cases belong to the given class. Discarded tests (i.e. ones with a false precondition) do not affect coverage.
For example:
prop_sorted_sort :: [Int] -> Property prop_sorted_sort xs = sorted xs ==> cover (length xs > 1) 50 "non-trivial" $ sort xs === xs
>>>quickCheck prop_sorted_sort*** Insufficient coverage after 100 tests (only 24% non-trivial, not 50%).
(==>) :: Testable prop => Bool -> prop -> Property infixr 0 Source #
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.
within :: Testable prop => Int -> prop -> Property Source #
Considers a property failed if it does not complete within the given number of microseconds.
forAll :: (Show a, Testable prop) => Gen a -> (a -> prop) -> Property Source #
Explicit universal quantification: uses an explicitly given test case generator.
forAllShrink :: (Show a, Testable prop) => Gen a -> (a -> [a]) -> (a -> prop) -> Property Source #
Like forAll, but tries to shrink the argument for failing test cases.
(.&.) :: (Testable prop1, Testable prop2) => prop1 -> prop2 -> Property infixr 1 Source #
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 infixr 1 Source #
Conjunction: p1 .&&. p2 passes if both p1 and p2 pass.
(.||.) :: (Testable prop1, Testable prop2) => prop1 -> prop2 -> Property infixr 1 Source #
Disjunction: p1 .||. p2 passes unless p1 and p2 simultaneously fail.