Issue in QuickCheckHeap#genHeap function

[lucaslabs]

Hi Gleb,

Just cloned your quickcheck example solution and, first of all, I'd like to say that is a great and self explanatory example :)

The thing is that the code is not compiling.

The issue is in the QuickCheckHeap#genHeap function:

lazy val genHeap: Gen[H] = for {
    a <- arbitrary[Int]
    h <- oneOf(value(empty), genHeap)
  } yield insert(a, h)

The specific issue is for the value method. The Eclipse Problems tab says: "not found: value value".

Any help?

[glebd]

It's been a while since I touched this code, but IIRC I was using IntelliJ IDEA -- maybe it's an Eclipse issue? Or maybe it's due to changes in a later version of Scala?

[lucaslabs]

Yes, I was thinking about Scala version.

[dgomesbr]

It's the scala version, but guys play fair and try to create your own. The corrected version for the scala should use const instead of value:

  lazy val genHeap: Gen[H] = for {
    v <- arbitrary[Int]
    h <- oneOf(const(empty), genHeap)
  } yield insert(v, h)

this fix #1

[lucaslabs]

Yes @dgomesbr, that do the trick/fix. Thanks for the answer :)

[sigmabooma]

" This issue is the value() function. Try using Gen.const(empty), genHeap "

[abossenbroek]

Somehow I get a NullPointerException with this implementation,

val genQueue = for {
    v <- arbitrary[Int]
    orgQueue <- genHeap
  } yield insert(v, orgQueue)

  val meldQueue = for {
    q1 <- genHeap
    q2 <- genHeap
  } yield meld(q1, q2)

  lazy val genHeap: Gen[H] = oneOf(const(empty), genQueue, meldQueue)

any tips on what could possibly cause this, I am interested in learning from my mistakes.