Workaround for Mockito's issue with mocking AnyVal as described here: https://stackoverflow.com/questions/27289757/mockito-matchers-scala-value-class-and-nullpointerexception - requires shapeless

MockitoScalaMagic.scala

import org.mockito.ArgumentMatchers.{eq => is}
import shapeless.ops.hlist.IsHCons
import shapeless._

trait MockitoScalaMagic {
  def isAnyVal[A <: AnyVal, V, VN <: HList](
    v: A
  )(implicit LB: Generic.Aux[A, VN], ev: IsHCons.Aux[VN, V, HNil], same: (V :: HNil) =:= VN): A =
    LB.from(is(ev.head(LB.to(v))) :: HNil)

}