Specs2 won't print scalacheck counterexamples? - scala

Question

I'm using specs2 to run my tests. I'm able to get it running scalacheck, but in the below (when I run with sbt test) it doesn't print the counterexample. This is almost useless without the counterexample:
import org.specs2.mutable.Specification
import org.scalacheck.Properties
import org.scalacheck.Prop
import org.specs2.ScalaCheck
import org.specs2.scalacheck.Parameters
import org.scalacheck.Gen
class StripeExportSpec extends Specification with ScalaCheck {
import StripeExportJob._
//.verbose makes no difference
implicit val params = Parameters().setVerbosity(10)
val p2: Properties = new Properties("dayIntervals") {
val dayEpochs = for {
n <- Gen.choose(1l, 500l)
m <- Gen.choose(n, 500l)
} yield (n*twentyFourHours,m*twentyFourHours)
property("aligns start to first parameter") = Prop.forAll(dayEpochs) { x: (Long,Long) =>
val (a, b) = x
val result = dayIntervals(a, b)
result.head._1 == a
}
property("aligns end correctly to 24 hours after b") = Prop.forAll(dayEpochs) { x: (Long,Long) =>
val (a, b) = x
val result = dayIntervals(a, b)
result.last._2 == b+twentyFourHours
}
}
//s2"dayIntervals respects ${properties(p2)}"
"dayIntervals respects " >> addFragments(properties(p2))
}
Instead all I get is:
[info] StripeExportSpec
[info]
[info] dayIntervals respects
[info]
[error] ! dayIntervals.aligns start to first parameter
[error] java.lang.AssertionError: assertion failed (StripeExport.scala:157)
[error] com.handy.pipeline.jobs.StripeExportJob$.dayIntervals(StripeExport.scala:157)
[error] com.handy.pipeline.jobs.StripeExportSpec$$anon$1$$anonfun$2.apply(StripeExportSpec.scala:28)
[error] com.handy.pipeline.jobs.StripeExportSpec$$anon$1$$anonfun$2.apply(StripeExportSpec.scala:26)
[error] org.scalacheck.Prop$$anonfun$forAllShrink$1$$anonfun$3.apply(Prop.scala:713)
[error] org.scalacheck.Prop$$anonfun$forAllShrink$1$$anonfun$3.apply(Prop.scala:713)
[error] org.scalacheck.Prop$.secure(Prop.scala:457)
[error] org.scalacheck.Prop$$anonfun$forAllShrink$1.org$scalacheck$Prop$$anonfun$$result$1(Prop.scala:713)
[error] org.scalacheck.Prop$$anonfun$forAllShrink$1$$anonfun$4.apply(Prop.scala:720)
[error] org.scalacheck.Prop$$anonfun$forAllShrink$1$$anonfun$4.apply(Prop.scala:720)
[error] org.scalacheck.Prop$$anonfun$forAllShrink$1.getFirstFailure$1(Prop.scala:720)
[error] org.scalacheck.Prop$$anonfun$forAllShrink$1.shrinker$1(Prop.scala:730)
[error] org.scalacheck.Prop$$anonfun$forAllShrink$1.apply(Prop.scala:752)
[error] org.scalacheck.Prop$$anonfun$forAllShrink$1.apply(Prop.scala:707)
[error] org.scalacheck.Prop$$anonfun$apply$5.apply(Prop.scala:292)
[error] org.scalacheck.Prop$$anonfun$apply$5.apply(Prop.scala:291)
[error] org.scalacheck.PropFromFun.apply(Prop.scala:22)
[error] org.scalacheck.Test$.org$scalacheck$Test$$workerFun$1(Test.scala:294)
[error] org.scalacheck.Test$$anonfun$3.apply(Test.scala:323)
[error] org.scalacheck.Test$$anonfun$3.apply(Test.scala:323)
[error] org.scalacheck.Platform$.runWorkers(Platform.scala:40)
[error] org.scalacheck.Test$.check(Test.scala:323)
[error] com.handy.pipeline.jobs.StripeExportSpec.check(StripeExportSpec.scala:14)
[info]
[error] ! dayIntervals.aligns end correctly to 24 hours after b
[error] java.lang.AssertionError: assertion failed (StripeExport.scala:157)
[error] com.handy.pipeline.jobs.StripeExportJob$.dayIntervals(StripeExport.scala:157)
[error] com.handy.pipeline.jobs.StripeExportSpec$$anon$1$$anonfun$5.apply(StripeExportSpec.scala:34)
[error] com.handy.pipeline.jobs.StripeExportSpec$$anon$1$$anonfun$5.apply(StripeExportSpec.scala:32)
[error] org.scalacheck.Prop$$anonfun$forAllShrink$1$$anonfun$3.apply(Prop.scala:713)
[error] org.scalacheck.Prop$$anonfun$forAllShrink$1$$anonfun$3.apply(Prop.scala:713)
[error] org.scalacheck.Prop$.secure(Prop.scala:457)
[error] org.scalacheck.Prop$$anonfun$forAllShrink$1.org$scalacheck$Prop$$anonfun$$result$1(Prop.scala:713)
[error] org.scalacheck.Prop$$anonfun$forAllShrink$1$$anonfun$4.apply(Prop.scala:720)
[error] org.scalacheck.Prop$$anonfun$forAllShrink$1$$anonfun$4.apply(Prop.scala:720)
[error] org.scalacheck.Prop$$anonfun$forAllShrink$1.getFirstFailure$1(Prop.scala:720)
[error] org.scalacheck.Prop$$anonfun$forAllShrink$1.shrinker$1(Prop.scala:730)
[error] org.scalacheck.Prop$$anonfun$forAllShrink$1.apply(Prop.scala:752)
[error] org.scalacheck.Prop$$anonfun$forAllShrink$1.apply(Prop.scala:707)
[error] org.scalacheck.Prop$$anonfun$apply$5.apply(Prop.scala:292)
[error] org.scalacheck.Prop$$anonfun$apply$5.apply(Prop.scala:291)
[error] org.scalacheck.PropFromFun.apply(Prop.scala:22)
[error] org.scalacheck.Test$.org$scalacheck$Test$$workerFun$1(Test.scala:294)
[error] org.scalacheck.Test$$anonfun$3.apply(Test.scala:323)
[error] org.scalacheck.Test$$anonfun$3.apply(Test.scala:323)
[error] org.scalacheck.Platform$.runWorkers(Platform.scala:40)
[error] org.scalacheck.Test$.check(Test.scala:323)
[error] com.handy.pipeline.jobs.StripeExportSpec.check(StripeExportSpec.scala:14)

Answer 1

This is a bug in specs2 which occurs when you throw AssertionErrors (or any kind of java.lang.Error in properties. This is fixed in 3.8.4-20160905063548-8470e96.
Also, since you are using a specification you don't have to use ScalaCheck Properties. You can write:
"dayIntervals" >> {
"aligns start to first parameter" >> Prop.forAll(dayEpochs) { x: (Long,Long) =>
val (a, b) = x
val result = dayIntervals(a, b)
result.head._1 === a
}
// another way of using generators
"aligns end correctly to 24 hours after b" >> prop { x: (Long,Long) =>
val (a, b) = x
val result = dayIntervals(a, b)
result.last._2 === b+twentyFourHours
}.setGen(dayEpochs)
}
val dayEpochs = for {
n <- Gen.choose(1l, 500l)
m <- Gen.choose(n, 500l)
} yield (n*twentyFourHours,m*twentyFourHours)