### Question:
AggregatorsHelper { public static List<AggregatorFactory> build(String rawAggregators) { List<AggregatorFactory> aggregators = new ArrayList<AggregatorFactory>(); aggregators.add(new CountAggregatorFactory("count")); return aggregators; }  static List<AggregatorFactory> build(String rawAggregators);  }### Answer:
@Test public void buildWithEmptyList() { String emptyList = ""; Assertions.assertThat(AggregatorsHelper.build(emptyList)).isEqualTo(expectedList); }
@Test public void buildWithNoValidList() { String emptyList = ",,21$%"; Assertions.assertThat(AggregatorsHelper.build(emptyList)).isEqualTo(expectedList); }
@Test public void buildWithValidList() { String emptyList = "count,longSum,doubleSum"; Assertions.assertThat(AggregatorsHelper.build(emptyList)).isEqualTo(expectedList); }