In GeneratorDrivenPropertyChecks, a property evaluation is discarded if it throws
DiscardedEvaluationException, which is produced by a whenever clause that
evaluates to false. For example, consider this ScalaTest property check:
// forAll defined in GeneratorDrivenPropertyChecks
forAll { (n: Int) =>
whenever (n > 0) {
doubleIt(n) should equal (n * 2)
}
}
In the above code, whenever a non-positive n is passed, the property function will complete abruptly
with DiscardedEvaluationException.
Similarly, in Checkers, a property evaluation is discarded if the expression to the left
of ScalaCheck's ==> operator is false. Here's an example:
// forAll defined in Checkers
forAll { (n: Int) =>
(n > 0) ==> doubleIt(n) == (n * 2)
}
For either kind of property check, MaxDiscardedFactor indicates the maximum fraction of
total tests that may be discarded, relative to the number of successful tests. For example, if this
is set to 4.0, and you are running 100 tests, it may discard up to 400 tries before considering the
test to be org.scalatest.prop.PropertyCheckResult.Exhausted.
value
the permitted number of discarded tests, as a multiple of successful ones.
A PropertyCheckConfigParam that specifies how many generated values may be discarded, as a multiple of the successful attempts, before the property check is considered to be org.scalatest.prop.PropertyCheckResult.Exhausted.
In
GeneratorDrivenPropertyChecks, a property evaluation is discarded if it throwsDiscardedEvaluationException, which is produced by awheneverclause that evaluates to false. For example, consider this ScalaTest property check:In the above code, whenever a non-positive
nis passed, the property function will complete abruptly withDiscardedEvaluationException.Similarly, in
Checkers, a property evaluation is discarded if the expression to the left of ScalaCheck's==>operator is false. Here's an example:For either kind of property check,
MaxDiscardedFactorindicates the maximum fraction of total tests that may be discarded, relative to the number of successful tests. For example, if this is set to 4.0, and you are running 100 tests, it may discard up to 400 tries before considering the test to be org.scalatest.prop.PropertyCheckResult.Exhausted.the permitted number of discarded tests, as a multiple of successful ones.