scala libraryDependencies += "org.scalatest" %% "scalatest" % "3.2.9" % Test scala import org.scalatest.flatspec.AnyFlatSpec class ExampleSpec extends AnyFlatSpec { "A Stack" should "pop values in last-in-first-out order" in { val stack = new Stack[Int] stack.push(1) stack.push(2) assert(stack.pop() === 2) assert(stack.pop() === 1) } }