### Question:
CmsPeriod implements ImmutableBean, Serializable { public static CmsPeriod.Builder builder() { return new CmsPeriod.Builder(); } @ImmutableConstructor private  CmsPeriod(
      Currency currency,
      double notional,
      LocalDate startDate,
      LocalDate endDate,
      LocalDate unadjustedStartDate,
      LocalDate unadjustedEndDate,
      double yearFraction,
      LocalDate paymentDate,
      LocalDate fixingDate,
      Double caplet,
      Double floorlet,
      DayCount dayCount,
      SwapIndex index,
      ResolvedSwap underlyingSwap); CmsPeriodType getCmsPeriodType(); double getStrike(); CmsPeriod toCouponEquivalent(); static CmsPeriod.Meta meta(); static CmsPeriod.Builder builder(); @Override CmsPeriod.Meta metaBean(); Currency getCurrency(); double getNotional(); LocalDate getStartDate(); LocalDate getEndDate(); LocalDate getUnadjustedStartDate(); LocalDate getUnadjustedEndDate(); double getYearFraction(); LocalDate getPaymentDate(); LocalDate getFixingDate(); OptionalDouble getCaplet(); OptionalDouble getFloorlet(); DayCount getDayCount(); SwapIndex getIndex(); ResolvedSwap getUnderlyingSwap(); Builder toBuilder(); @Override boolean equals(Object obj); @Override int hashCode(); @Override String toString();  }### Answer:
@Test public void test_builder_nonNullCapFloor() { assertThatIllegalArgumentException() .isThrownBy(() -> CmsPeriod.builder() .caplet(STRIKE) .floorlet(STRIKE) .startDate(START) .endDate(END) .index(INDEX) .notional(NOTIONAL) .yearFraction(YEAR_FRACTION) .dayCount(ACT_360) .build()); }