variance_hw

Just for understanding variance in scala

Tasks:

implement all needed case class and case object for proposed traits

trait ContrVOrdering[-T] {
  def compare(a: T, b: T): Int
}

and

trait BiTree[+T] {
  def value: T
  def left: BiTree[T]
  def right: BiTree[T]
  def find(v: T): Option[T]
  def add[U/*Think about bound here*/](value: U)(implicit ord: ContrVOrdering[U]): BiTree[U]
}

write tests using scalatest
write tests using scalacheck

NOTE: Feel free to extend / change any interface if needed.