### Question:
LevelFactory { public abstract Level create(int level);  abstract Level create(int level);  }### Answer:
@Test public void getFirst() { assertThat(factory.create(1)).isNotNull(); }
@Test public void getSecond() { assertThat(factory.create(2)).isNotNull(); }
@Test public void getThird() { assertThat(factory.create(3)).isNotNull(); }
@Test public void getFourth() { assertThat(factory.create(4)).isNull(); }