### Question:
Ordinal implements Comparable<Ordinal> { public static Ordinal fromIndex(int zeroBased) { return of(zeroBased + 1); } private  Ordinal(int num); static Ordinal first(); static Stream<Ordinal> natural(); static Ordinal of(int oneBased); static Ordinal fromIndex(int zeroBased); int toIndex(); Ordinal next(); @Override int compareTo(Ordinal that); @Override int hashCode(); @Override boolean equals(Object obj); @Override String toString();  }### Answer:
@Test public void fromIndex() { for (int i = 0; i < 1000; i++) { assertThat(Ordinal.fromIndex(i).toIndex()).isEqualTo(i); } }