Kotlin and kotest with arbitrary values: what am I doing wrong? - kotlin

Question

I've gone through the kotest documentation and am trying to incorporate some property based testing into my code. From the documentation, my impression was that if you use a forAll<T>, if kotest has a built-in Arb<T>, it would generate arbitrary values for T and then run the given tests on them.
So then, why does this example which should clearly fail claim to pass for me?
class PassesExample: ShouldSpec({
should("I should fail") {
forAll<Int> { a ->
abs(a) shouldBe -1
}
}
})
The output is as follows:
> Task :wrapper
BUILD SUCCESSFUL in 98ms
1 actionable task: 1 executed
> Task :compileKotlin UP-TO-DATE
> Task :compileJava NO-SOURCE
> Task :processResources NO-SOURCE
> Task :classes UP-TO-DATE
> Task :compileTestKotlin UP-TO-DATE
> Task :compileTestJava NO-SOURCE
> Task :processTestResources NO-SOURCE
> Task :testClasses UP-TO-DATE
> Task :test
BUILD SUCCESSFUL in 1s
3 actionable tasks: 1 executed, 2 up-to-date
9:42:38 PM: Execution finished ':test --tests "abstractalgebra.PassesExample"'.
(Ignore the abstractalgebra... I'm trying to play around with some finite fields and just threw this in the same file as my test file.)
If I don't use the forAll<Int> and give it an obvious concrete fail case, everything works as expected, for example:
class PassesExample: ShouldSpec({
should("I should fail") {
abs(2) shouldBe -1
}
})
and I get:
expected:<-1> but was:<2>
Expected :-1
Actual :2
What am I doing wrong? It is obvious that no tests are executed at all, or this would not work.

Answer 1

Never mind: I found out the issue. I was importing the wrong forAll:
import io.kotest.data.forAll
when I should have been importing:
import io.kotest.property.forAll