### Question:
Child extends Base { @Override public Set<Integer> getSet() { return output; }  @Override Set<Integer> getSet();  }### Answer:
@Test public void test() { Child son = new Child(); son.add(1); son.add(2); son.add(3); Set<Integer> out = son.getSet(); int result = 0; for (Integer i : out) { result += i; } assertEquals("sum", 6, result); }
@Test public void test() { Child grand = new Child(); grand.add(1); grand.add(2); grand.add(3); Set<Integer> out = grand.getSet(); int result = 0; for (Integer i : out) { result += i; } assertEquals("sum", 6, result); }