### Question:
IborAveragedFixing implements ImmutableBean, Serializable { public static IborAveragedFixing ofDaysInResetPeriod( IborIndexObservation observation, LocalDate startDate, LocalDate endDate) { return ofDaysInResetPeriod(observation, startDate, endDate, null); } private  IborAveragedFixing(
      IborIndexObservation observation,
      Double fixedRate,
      double weight); static IborAveragedFixing of(IborIndexObservation observation); static IborAveragedFixing of(IborIndexObservation observation, Double fixedRate); static IborAveragedFixing ofDaysInResetPeriod(
      IborIndexObservation observation,
      LocalDate startDate,
      LocalDate endDate); static IborAveragedFixing ofDaysInResetPeriod(
      IborIndexObservation observation,
      LocalDate startDate,
      LocalDate endDate,
      Double fixedRate); static IborAveragedFixing.Meta meta(); static IborAveragedFixing.Builder builder(); @Override IborAveragedFixing.Meta metaBean(); IborIndexObservation getObservation(); OptionalDouble getFixedRate(); double getWeight(); Builder toBuilder(); @Override boolean equals(Object obj); @Override int hashCode(); @Override String toString();  }### Answer:
@Test public void test_ofDaysInResetPeriod_null() { assertThatIllegalArgumentException() .isThrownBy(() -> IborAveragedFixing.ofDaysInResetPeriod(null, date(2014, 7, 2), date(2014, 8, 2))); assertThatIllegalArgumentException() .isThrownBy(() -> IborAveragedFixing.ofDaysInResetPeriod(GBP_LIBOR_3M_OBS, null, date(2014, 8, 2))); assertThatIllegalArgumentException() .isThrownBy(() -> IborAveragedFixing.ofDaysInResetPeriod(GBP_LIBOR_3M_OBS, date(2014, 7, 2), null)); assertThatIllegalArgumentException() .isThrownBy(() -> IborAveragedFixing.ofDaysInResetPeriod(null, null, null)); assertThatIllegalArgumentException() .isThrownBy(() -> IborAveragedFixing.ofDaysInResetPeriod(null, date(2014, 7, 2), date(2014, 8, 2), 0.05)); assertThatIllegalArgumentException() .isThrownBy(() -> IborAveragedFixing.ofDaysInResetPeriod(GBP_LIBOR_3M_OBS, null, date(2014, 8, 2), 0.05)); assertThatIllegalArgumentException() .isThrownBy(() -> IborAveragedFixing.ofDaysInResetPeriod(GBP_LIBOR_3M_OBS, date(2014, 7, 2), null, 0.05)); assertThatIllegalArgumentException() .isThrownBy(() -> IborAveragedFixing.ofDaysInResetPeriod(null, null, null, null)); }