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GHC 9.10.3 · lts/ghc-9.10.x · 248f8f0 · 2026-10-05

ModuleQuickCheck-2.15.0.1Haskell2010

Test.QuickCheck.State

QuickCheck's internal state. Internal QuickCheck module.

2 types

PackageQuickCheck-2.15.0.1
Exports2
LanguageHaskell2010
LicenceBSD-3-Clause
SourceState.hs

datadata State

State represents QuickCheck's internal state while testing a property. The state is made visible to callback functions.

Constructors

MkState
- terminal :: Terminal
  the current terminal
- maxSuccessTests :: Int
  maximum number of successful tests needed
- maxDiscardedRatio :: Int
  maximum number of discarded tests per successful test
- coverageConfidence :: Maybe Confidence
  how to compute the size of test cases from #tests and #discarded tests
- numTotMaxShrinks :: !Int
  How many shrinks to try before giving up
- replayStartSize :: Maybe Int
  Size to start at when replaying
- maxTestSize :: !Int
  Maximum size of test
- numSuccessTests :: !Int
  the current number of tests that have succeeded
- numDiscardedTests :: !Int
  the current number of discarded tests
- numRecentlyDiscardedTests :: !Int
  the number of discarded tests since the last successful test
- labels :: !Map [String] Int
  counts for each combination of labels (label/collect)
- classes :: !Map String Int
  counts for each class of test case (classify/cover)
- tables :: !Map String (Map String Int)
  tables collected using tabulate
- requiredCoverage :: !Map (Maybe String, String) Double
  coverage requirements
- expected :: !Bool
  indicates the expected result of the property
- randomSeed :: !QCGen
  the current random seed
- numSuccessShrinks :: !Int
  number of successful shrinking steps so far
- numTryShrinks :: !Int
  number of failed shrinking steps since the last successful shrink
- numTotTryShrinks :: !Int
  total number of failed shrinking steps

datadata Confidence

The statistical parameters used by checkCoverage.

Constructors

Confidence
- certainty :: Integer
  How certain checkCoverage must be before the property fails. If the coverage requirement is met, and the certainty parameter is n, then you should get a false positive at most one in n runs of QuickCheck. The default value is 10^9.
  Lower values will speed up checkCoverage at the cost of false positives.
  If you are using checkCoverage as part of a test suite, you should be careful not to set certainty too low. If you want, say, a 1% chance of a false positive during a project's lifetime, then certainty should be set to at least 100 * m * n, where m is the number of uses of cover in the test suite, and n is the number of times you expect the test suite to be run during the project's lifetime. The default value is chosen to be big enough for most projects.
- tolerance :: Double
  For statistical reasons, checkCoverage will not reject coverage levels that are only slightly below the required levels. If the required level is p then an actual level of tolerance * p will be accepted. The default value is 0.9.
  Lower values will speed up checkCoverage at the cost of not detecting minor coverage violations.

Instances1Show

Show ConfidenceDefined in QuickCheck-2.15.0.1 · Test.QuickCheck.State