Tests

import org.scalatest.FunSuite
class C_Polynomial_Tests extends FunSuite {
  import polynomials.Polynomial.x
  import polynomials.{ C, S, X }
  val p1 = C(2)
  val p2 = C(3)
  val p3 = C(-5)
  val p4 = X(C(5))
  val p5 = S(1, S(2, C(3)))
  test("degree") {
    assert(p1.degree === 0)
    assert(p2.degree === 0)
    assert(p3.degree === 0)
    assert(p4.degree === 1)
    assert(p5.degree === 2)
  }
  test("eval") {
    assert(p1.eval(1) === 2.0)
    assert(p2.eval(0) === 3.0)
    assert(p3.eval(10) === -5.0)
    assert(p4.eval(2) === 10.0)
    assert(p5.eval(2) === 17.0)
  }
  test("+: Polynomial") {
    assert(p1 + p2 === C(5))
    assert(p1 + p3 === C(-3))
    assert(p2 + p3 === C(-2))
    assert(p1 + p2 + p3 === C(0))
    assert(p1 + p4 === S(2, C(5)))
  }
  test("-: Polynomial") {
    assert(p2 - p1 === C(1))
    assert(p3 - p1 === C(-7))
    assert(p5 - p3 === S(6, S(2, C(3))))
    assert(p4 - p5 ===  S(-1, S(3, C(-3))))
    assert(p4 - p1 === S(-2, C(5)))
  }
  test("*: Polynomial") {
    val p = X(S(6, X(S(12, X(C(9))))))
    assert(p.eval(1) === 27.0)
    assert(p1 * p2 === C(6))
    assert(p1 * p4 === X(C(10)))
    assert(p1 * p5 === S(2, S(4, C(6))))
    assert(p4 * p4 === X(X(C(25))))
    assert((p4*p4).degree === 2)
    assert(p5 * C(0) === C(0))
    assert(p5 * p5 === S(1,S(4,S(10,S(12,C(9))))))
    assert(p5 * p4 === X(S(5, S(10, C(15)))))
    assert(p4 * p5 === X(S(5, S(10, C(15)))))
    assert(p5 * C(0) === C(0))
    assert(p4 * C(0) === C(0))
    assert(p1 * C(0) === C(0))
  }
  test("Basic subtraction and simplification") {
    val f = X(S(2, C(3)))
    assert(p5 - f === C(1))
    val f2 = S(1, C(5))
    assert(p4 - f2 === C(-1))
    assert((p5 - C(1)).degree === 2)
    assert(p5 - C(1) === X(S(2, C(3))))
  }
  test("-: Unary Operator") {
    assert(-p1 === C(-2))
    assert(-p4 === X(C(-5)))
    assert(-p5 === S(-1, S(-2, C(-3))))
  }
  test("Derivative") {
    assert(p1.derivative === C(0))
    assert(p4.derivative === C(5))
    assert(p5.derivative === S(2, C(6)))
  }
  test("@@: Polynomial") {
    assert(p1 @@ 0 === C(1))
    assert(p4 @@ 0 === C(1))
    assert(p5 @@ 0 === C(1))
    assert(p1 @@ 3 === C(8))
    assert(p4 @@ 2 === X(X(C(25))))
    assert(p5 @@ 2 === S(1, S(4, S(10, S(12, C(9))))))
  }
  test("+, -, *: Integer") {
    assert(p1 + 10 === C(12))
    assert(p4 + 10 === S(10, C(5)))
    assert(p5 + 10 === S(11, S(2, C(3))))
    assert(p1 - 10 === C(-8))
    assert(p4 - 10 === S(-10, C(5)))
    assert(p5 - 10 === S(-9, S(2, C(3))))
    assert(p1 * 10 === C(20))
    assert(p4 * 10 === X(C(50)))
    assert(p5 * 10 === S(10, S(20, C(30))))
  }
  test("exceptions") {
    assertThrows[IllegalArgumentException](p1 @@ -1)
    assertThrows[IllegalArgumentException](p4 @@ -1)
    assertThrows[IllegalArgumentException](p5 @@ -1)
  }
}