### Question:
Size { public Size add(Size aSize) { return new Size(width + aSize.getWidth(), height + aSize.getHeight()); } Size();  Size(int width, int height); void setWidth(int width); void setHeight(int height); int getWidth(); int getHeight(); @Override String toString(); @Override boolean equals(Object o); @Override int hashCode(); Size minus(Size aSize); Size add(Size aSize); Size append(int width, int height); Size append(Size aSize); static final Size ZERO_SIZE; }### Answer:
@Test public void addition() { Size size1 = new Size(20, 10); Size size2 = new Size(10, 5); Size result = size1.add(size2); assertEquals("Sum is incorrect", new Size(30, 15), result); }