Tests

//test: StudentTest

import org.scalatest.FunSuite
import Solution._

class StudentTest extends FunSuite {

  test("listFrom") {
    assertResult(Element(3, Element(2, Element(1, Empty())))) {
      listFrom(3)
    }
  }

  test("listFromEdge") {
    assertResult(Empty()) {
      listFrom(0)
    }
  }

  test("sumIntList") {
    assertResult(10) {
      sumIntList(Element(1, Element(2, Element(3, Element(4, Empty())))))
    }
  }

  test("sumIntListEdge") {
    assertResult(0) {
      sumIntList(Empty())
    }
  }

  test("headEdge") {
    assertThrows[NoSuchElementException] { // alternative: intercept[NoSuchElementException]
      head(Empty())
    }
  }

  test("head") {
    assertResult(1) {
      head(Element(1, Element(2, Element(3, Empty()))))
    }
  }

  test("tailEdge") {
    assertThrows[NoSuchElementException] { // alternative: intercept[NoSuchElementException]
      tail(Empty())
    }
  }

  test("tail") {
    assertResult(Element(2, Element(3, Empty()))) {
      tail(Element(1, Element(2, Element(3, Empty()))))
    }
  }


  test("Head empty") {
    intercept[NoSuchElementException] {
      head(Empty())
    }
  }

  test("Tail") {
    assertResult(Element(3, Empty())) {
      tail(Element(34, Element(3, Empty())))
    }
  }


  test("Concat more elements xs.size() > ys.size()") {
    assertResult(Element(34, Element(3, Element(6, Empty())))) {
      concat(Element(34, Element(3, Empty())), Element(6, Empty()))
    }
  }

  test("Concat more elements xs.size() < ys.size()") {
    assertResult(Element(3, Element(34, Element(6, Empty())))) {
      concat(Element(3, Empty()), Element(34, Element(6, Empty())))
    }
  }

  test("Concat more elements xs.size() == ys.size()") {
    assertResult(Element(1, Element(6, Empty()))) {
      concat(Element(1, Empty()), Element(6, Empty()))
    }
  }

  test("Concat xs Nil") {
    assertResult(Element(6, Empty())) {
      concat(Empty(), Element(6, Empty()))
    }
  }

  test("Concat ys Nil") {
    assertResult(Element(6, Empty())) {
      concat(Element(6, Empty()), Empty())
    }
  }

  test("Concat both xs & ys Nils") {
    assertResult(Empty()) {
      concat(Empty(), Empty())
    }
  }

  test("take n > size()") {
    assertResult(Element(34, Element(3, Element(6, Empty())))) {
      take(10, Element(34, Element(3, Element(6, Empty()))))
    }
  }

  test("take n == size()") {
    assertResult(Element(34, Element(3, Element(6, Empty())))) {
      take(3, Element(34, Element(3, Element(6, Empty()))))
    }
  }

  test("take n < size()") {
    assertResult(Element(34, Element(3, Empty()))) {
      take(2, Element(34, Element(3, Element(6, Empty()))))

    }
  }

  test("take n == 1") {
    assertResult(Element(34, Empty())) {
      take(1, Element(34, Element(3, Element(6, Empty()))))

    }
  }


  test("drop n == 0") {
    assertResult(Element(34, Element(3, Element(6, Empty())))) {
      drop(0, Element(34, Element(3, Element(6, Empty()))))
    }
  }

  test("drop n == 1") {
    assertResult(Element(3, Element(6, Empty()))) {
      drop(1, Element(34, Element(3, Element(6, Empty()))))
    }
  }

  test("drop n == size()") {
    assertResult(Empty()) {
      drop(3, Element(34, Element(3, Element(6, Empty()))))
    }
  }

   test("drop n > size()") { // same behavior as n == size()
    assertResult(Empty()) {
      drop(4, Element(34, Element(3, Element(6, Empty()))))
    }
  }
}