/** The test case class for the ArithExpr composite hierarchy. */
class ArithExprTest extends TestCase {
  
  static Double EPSILON = 1.1e-16;
  
  static Const zero = new Const(0.);
  static Const negSeven = new Const(-7.);
  static Const five = new Const(5.);
  static Const negTen = new Const(-10.);
  static Const ten = new Const(10.);
  static Const twentyFive = new Const(25.);
  
  static Var x = new Var("x");
  static Var y = new Var("y");
  static Var z = new Var("z");
  
  /** Tests the eval() method in the ArithExpr composite. */
  public void testExprPrint() {
    assertEquals("const 0.", "0.0", zero.exprString());
    assertEquals("const -7.", "-7.0", negSeven.exprString());
    assertEquals("const -10.", "-10.0", negTen.exprString());
    assertEquals("5 + 5",  "(5.0 + 5.0)", new Sum(five, five).exprString());
    assertEquals("5 * 10", "(5.0 * 10.0)", new Prod(five, ten).exprString());
    assertEquals("10/5", "(10.0 / 5.0)", new Quot(ten, five).exprString());
    assertEquals("10 - 5", "(10.0 - 5.0)", new Diff(ten, five).exprString());
    assertEquals("x * x", "(x * x)", new Prod(x, x).exprString());
    assertEquals("y/z", "(y / z)", new Quot(y, z).exprString());              
  }
  
  static EmptyEnv e = EmptyEnv.ONLY;
  static Env env1 = e.cons("x", -10.).cons("y", 25.).cons("z", -5.);
  
  /** Tests the eval() method in the ArithExpr composite. */
  public void testEval() {
    assertEquals("const 0.", 0., zero.eval(e), EPSILON);
    assertEquals("const 7.", -7., negSeven.eval(e), EPSILON);
    assertEquals("const -10.", -10., negTen.eval(e), EPSILON);
    assertEquals("25 + 5",  30., new Sum(twentyFive, five).eval(e), EPSILON);
    assertEquals("-7 * 10", -70., new Prod(negSeven, ten).eval(e), EPSILON);
    assertEquals("25/5", 5., new Quot(twentyFive, five).eval(e), EPSILON);
    assertEquals("25 - 5", 20., new Diff(twentyFive, five).eval(e), EPSILON);
    assertEquals("x * z", 50., new Prod(negTen, z).eval(env1), EPSILON);
    assertEquals("y/z", -5., new Quot(y, z).eval(env1), EPSILON);              
  }
}