### Question:
ParametricPlane { public Vector getDirectionY() { return directionY; } ParametricPlane(Point3D basePoint, Vector directionX,
        Vector directionY, Vector normal);  ParametricPlane(Point3D basePoint, Vector directionX, Vector directionY);  ParametricPlane(Point3D basePoint, Point3D b, Vector normal);  ParametricPlane(Point3D basePoint, Point3D b, Point3D c);  ParametricPlane(Extrusion e); Point3D getPoint(double x, double y); Point3D getPoint(Point3D point); double[] getParameter(Point3D p); boolean isOnPlane(Point3D p); Point3D getBasePoint(); void setBasePoint(Point3D base); Vector getDirectionX(); void setDirectionX(Vector directionX); Vector getDirectionY(); void setDirectionY(Vector directionY); Vector getNormal();  }### Answer:
@Test public void directionY() { ParametricPlane p = new ParametricPlane(new Point3D(0, 0, 0), new Point3D(1, 0, 0), new Vector(0, 0, 1)); Vector y = p.getDirectionY(); assertEquals(0.0, y.getX(), DELTA); assertEquals(1.0, y.getY(), DELTA); assertEquals(0.0, y.getZ(), DELTA); }
@Test public void directionX() { ParametricPlane p = new ParametricPlane(new Point3D(0, 0, 0), new Point3D(0, 1, 0), new Vector(0, 0, 1)); Vector y = p.getDirectionY(); assertEquals(-1.0, y.getX(), DELTA); assertEquals(0.0, y.getY(), DELTA); assertEquals(0.0, y.getZ(), DELTA); }