Scala mock, MockFactory expects fails with 'Unexpected call' - scala

Question

I'm trying to follow this doc - scalatest with scala-mock to mock the function and check if it has been called
class AggregateSpec extends FlatSpec with Matchers with MockFactory {
val data = Seq("This", "is", "something", "I", "would", "like", "to", "know")
"combop function" should "BE called for par collection" in {
val mockCombop = mockFunction[Int, Int, Int]
val parData = data.par
val result: Int = parData.aggregate(0)(
seqop = (acc, next) => acc + next.length,
combop = mockCombop
)
result should === (31)
mockCombop.expects(*, *).atLeastOnce()
}
}
As result:
> [info] - should BE called for non-par collection *** FAILED *** [info]
> Unexpected call: MockFunction2-1(4, 2) [info] [info] Expected:
> [info] inAnyOrder { [info] [info] } [info] [info] Actual:
> [info] MockFunction2-1(9, 1) [info] MockFunction2-1(2, 4)
> [info] MockFunction2-1(4, 2) [info] MockFunction2-1(5, 4)
> (Option.scala:121)
Why? How to make it pass with scalatest + scala-mock ?
--
As deps I use:
libraryDependencies += "org.scalactic" %% "scalactic" % "3.0.1",
libraryDependencies += "org.scalatest" %% "scalatest" % "3.0.1" % "test",
libraryDependencies += "org.scalamock" %% "scalamock-scalatest-support" % "3.5.0"

Answer 1

You need to call mockCombop.expects before mockCombop gets called, not after:
"combop function" should "BE called for par collection" in {
val mockCombop = mockFunction[Int, Int, Int]
val parData = data.par
mockCombop.expects(*, *).atLeastOnce()
val result: Int = parData.aggregate(0)(
seqop = (acc, next) => acc + next.length,
combop = mockCombop
)
result should === (31)
}