Safe Haskell	None
Language	Haskell2010

Test.Falsify.Driver

Contents

Options
Results
- Additional accessors

Description

The main falsify driver

The main entrypoint into falsify is the falsify function, which attempts to falsify the Property' it is given. However, most users don't need to use this module directly; it is primarily intended for integration of falsify in test frameworks such as tasty. For the case of tasty specifically, see the tasty-falsify package.

Synopsis

falsify :: Options -> Property' e a -> IO (TestOutcome' e a)
data Options = Options {
- tests :: Word
- maxShrinks :: Maybe Word
- replay :: Maybe ReplaySeed
- maxRatio :: Word
}
data ReplaySeed = ReplaySeed {
- replaySeed :: Word64
- replayGamma :: Word64
}
data ExpectFailure
- = ExpectFailure
- | DontExpectFailure
data Verbose
- = Verbose
- | NotVerbose
parseReplaySeed :: String -> Either String ReplaySeed
type TestOutcome = TestOutcome' String
data TestOutcome' e a
data RenderedTestOutcome = RenderedTestOutcome {
- testPassed :: Bool
- testOutput :: String
}
renderTestOutcome :: Verbose -> ExpectFailure -> TestOutcome () -> RenderedTestOutcome
successes :: TestOutcome' e a -> [(ReplaySeed, a)]
discarded :: TestOutcome' e a -> Word
failure :: TestOutcome' e a -> Maybe (ReplaySeed, e)
failure' :: TestOutcome' e a -> Maybe (ReplaySeed, NonEmpty e)

Documentation

falsify :: Options -> Property' e a -> IO (TestOutcome' e a) Source #

Run a test: attempt to falsify the given property

Options

data Options Source #

Options for running a test

Constructors

Options
Fields tests :: Word Number of test cases to generate maxShrinks :: Maybe Word Number of shrinks allowed before failing a test replay :: Maybe ReplaySeed Random seed to use for replaying a previous test run maxRatio :: Word Maximum number of discarded test per successful test

Instances

Instances details

Default Options Source #
Instance details Defined in Test.Falsify.Internal.Driver Methods def :: Options #

data ReplaySeed Source #

Replay seed

By default, when we falsify a property we start with a PRNG initialized using a random seed (produced using the system entropy; this relies on initSMGen in splitmix). When a property fails, we will report the exact seed used, so that the user can re-run the exact same test again, if desired.

The definition of ReplaySeed is part of falsify's public API, to make it possible to use custom drivers.

Constructors

ReplaySeed
Fields replaySeed :: Word64 Seed replayGamma :: Word64 Gamma (must be odd)

Instances

Instances details

IsString ReplaySeed Source #
Instance details Defined in Test.Falsify.Internal.Driver.ReplaySeed Methods fromString :: String -> ReplaySeed #
Show ReplaySeed Source #
Instance details Defined in Test.Falsify.Internal.Driver.ReplaySeed Methods showsPrec :: Int -> ReplaySeed -> ShowS # show :: ReplaySeed -> String # showList :: [ReplaySeed] -> ShowS #
Binary ReplaySeed Source #
Instance details Defined in Test.Falsify.Internal.Driver.ReplaySeed Methods put :: ReplaySeed -> Put # get :: Get ReplaySeed # putList :: [ReplaySeed] -> Put #

data ExpectFailure Source #

Do we expect the property to fail?

If ExpectFailure, the test will fail if the property does not fail. Note that if we expect failure for a property, then we can stop at the first failed test; the number of tests to run for the property becomes a maximum rather than a goal.

Constructors

ExpectFailure
DontExpectFailure

data Verbose Source #

Verbose output

Note that if a test fails (and we were not expecting failure) we show the logs independent of verbosity.

Constructors

Verbose
NotVerbose

parseReplaySeed :: String -> Either String ReplaySeed Source #

Parse ReplaySeed

Returns Left an error message if parsing failed.

Results

type TestOutcome = TestOutcome' String Source #

TestOutcome specialized to String for errors

This mimicks the Property' vs Property distinction.

data TestOutcome' e a Source #

Result of running falsify

This is an opaque type; see renderTestOutcome and the additional accessors provided in Test.Falsify.Driver.

data RenderedTestOutcome Source #

Test outcome as it should be shown to the user

The rendered test outcome can usually be used directly in test framework integration. For example, the tasty integration uses

toTastyResult :: RenderedTestOutcome -> Tasty.Result
toTastyResult RenderedTestOutcome{testPassed, testOutput}
  | testPassed = Tasty.testPassed testOutput
  | otherwise  = Tasty.testFailed testOutput

Constructors

RenderedTestOutcome
Fields testPassed :: Bool testOutput :: String

renderTestOutcome :: Verbose -> ExpectFailure -> TestOutcome () -> RenderedTestOutcome Source #

Render test outcome

See RenderedTestOutcome for discussion.

Additional accessors

successes :: TestOutcome' e a -> [(ReplaySeed, a)] Source #

Successful test outcomes

NOTE: Normally the a parameter for a top-level property is instantiated to unit (()), in which case it's really only the length of the list of successes that is relevant.

discarded :: TestOutcome' e a -> Word Source #

Number of discarded test

failure :: TestOutcome' e a -> Maybe (ReplaySeed, e) Source #

Failing test, if any

Returns the error after shrinking

failure' :: TestOutcome' e a -> Maybe (ReplaySeed, NonEmpty e) Source #

Generalization of failure that returns the full shrinking history