### Question:
DayImpression implements Serializable { public void setDate(String date) { this.date = date; } DayImpression(String date, List<Impression> hours);  DayImpression();  DayImpression(Double[] dayCounts);  DayImpression(Object hoursMap); String getDate(); void setDate(String date); List<Impression> getHours(); void setHours(List<Impression> hours); void initAggregate(double[] aggregatedHCounts); long countImpressions(double price, TargetingChannel.PriceModel priceModel); static DayImpression add(DayImpression d1, DayImpression d2); static DayImpression buildEmptyDayImpression(String date); static DayImpression subtract(DayImpression d1, DayImpression d2); static DayImpression multiply(DayImpression d1, double r); @Override String toString();  }### Answer:
@Test public void setDate() { Double[] dayCnt = new Double[4]; dayCnt[0] = 0.0; dayCnt[1] = 1.1; dayCnt[2] = 2.2; dayCnt[3] = 3.3; DayImpression di = new DayImpression(dayCnt); String day = "20180105"; di.setDate(day); assertEquals(day, di.getDate()); }