Tuple2D extends Point2D.Double implements ILocated2D { public Tuple2D(double x, double y) { super(x, y); } Tuple2D(double x, double y); boolean isZero(); double length(); Tuple2D normalize(); double angle(); Tuple2D midpoint(Tuple2D position); Tuple2D add(Tuple2D position); Tuple2D sub(ILocated2D rhs); Tuple2D mult(double i); Tuple2D div(double i); Tuple2D getPosition(); Tuple2D rotate(double radians); double distance(ILocated2D other); @Override String toString(); double angleBetweenTargets(ILocated2D a, ILocated2D b);  }
@Test public void testTuple2D() { Tuple2D test = new Tuple2D(1, 2); assertEquals(test.x, 1, ERROR); assertEquals(test.y, 2, ERROR); }