Fields

• maxSuccess :: Int

  Max number of passed tests.

• maxDiscardRatio :: Int

  Max discard ratio.

• timeout :: Maybe Integer

  Campaign time budget in seconds (has precedence over maxSuccess).

• expect :: Bool

  Whether the property is expected to hold (True) or to fail (False).

• maxGenSize :: Int

  Max generation size passed to a generator. It uses the same formula for computing sizes as vanilla QuickCheck when in generation mode. Random mutations are generated using the maximum size.

• randomMutations :: Int

  Number of times to sample the generator associated to a random mutant. It can be automatically increased over time if autoResetAfter is not set to Nothing.

• maxMutationDepth :: Maybe Int

  The maximum number of ancestors a test case can have before being discarded. Useful to avoid mutating recursive structures indefinetely. Defaults to maxGenSize if set to Nothing.

• autoResetAfter :: Maybe Int

  Reset the global trace log if no interesting test case is found after a certain number of tests. If not set to Nothing, this will duplicate the current limit on every reset. Additionally, it also duplicates the randomMutations parameter.

• lazyPruning :: LazyPruningMode

  Use lazy pruning to avoid mutating unevaluated subexpressions. The target mutable subexpressions are ordered by last evaluated first.

• mutationOrder :: MutationOrder

  If lazyPruning is set to False, *every* subexpression of an interesting test case is mutated regardless whether it was evaluated or not. These subexpressions are ordered using a generic tree traversal order (level order by default). The provided options are: levelorder, preorder, and postorder, but you're free to define your own tree traversal order if needed.

• useFragments :: Bool

  Explode the interesting test cases found during the test loop into typed fragments. These fragments can be used to concretize fragment mutants.

• randomFragments :: Int

  The amount of fragments sampled from the global fragment store when concretizing a fragment mutant. Can return less than randomFragments test cases if there are not enough fragments of the type of the target subexpression to sample from.

• filterFragments :: FragmentTypeFilter

  Filter to allow or deny values of certain types from being saved in the fragment store.

• examples :: [Args]

  Initial inputs examples used to populate the global fragment store before the testing loop starts.

• traceBackend :: TraceBackend

  The tracing mechanism. Either Tree or Bitmap. Tree uses prefix-based traces (quite expensive but more precise). Bitmap uses edge-based traces (cheaper but less precise).

• maxTraceLength :: Maybe Int

  The maximim trace length to consider. Nodes added beyond this limit will be ignored. This is useful to limit memory consumption when using the Tree TraceBackend while testing lengthy properties.

• keepGoing :: Bool

  Whether to keep searching for more counterexamples after finding the first one. If set, Mutagen will stop only when reaching the maximum number of successful tests or the timeout, without giving up in the presence of too many discards. Reports will always be a Success.

  NOTE: you probably want to set saveCounterexamples when enabling this.

• saveCounterexamples :: Maybe FilePath

  If set to a FilePath, save found counterexamples to the given path. Accepts templated file paths via @, e.g., "counterexample_@.hs", where @ is be replaced by a counter. This is useful in combination with keepGoing to save multiple counterexamples over a long testing campaign.

  NOTE: if keepGoing is enabled and the counterexample path does not contain @, then the counter is appended at the end.

• chatty :: Bool

  Print extra info.

• debug :: DebugMode

  Whether to enable interactive debugging mode.

• tui :: Bool

  Whether to use a terminal user interface (TUI) for displaying progress.