### Question:
SolrFieldAdder { public void addCompositeField(SolrInputDocument doc, F field, List<String> values) { if (values.size() > 0) { String compositedValues = values.stream().collect(Collectors.joining(IndexFieldsConstants.VALUE_ATTRIBUTE_SEPARATOR)); if (StringUtils.isNotBlank(compositedValues)) { doc.addField(field.getFieldName(), compositedValues); } } }  void addField(SolrInputDocument doc, F field, String value); void addField(SolrInputDocument doc, F field, long value); void addField(SolrInputDocument doc, F field, String fieldPostfix, String value); void addCompositeField(SolrInputDocument doc, F field, List<String> values); void addDateField(SolrInputDocument doc, F field, LocalDate date); void addCurrencyField(SolrInputDocument doc, F field, BigDecimal value);  }### Answer:
@Test public void addCompositeField() { SolrInputDocument doc = new SolrInputDocument(); fieldAdder.addCompositeField(doc, JudgmentIndexField.JUDGE, Lists.newArrayList("Jan Kowalski", "PRESIDING_JUDGE", "REPORTING_JUDGE")); assertSingleField(doc, "judge", "Jan Kowalski|PRESIDING_JUDGE|REPORTING_JUDGE"); }
@Test public void addCompositeField_SINGLE() { SolrInputDocument doc = new SolrInputDocument(); fieldAdder.addCompositeField(doc, JudgmentIndexField.JUDGE, Lists.newArrayList("Jan Kowalski")); assertSingleField(doc, "judge", "Jan Kowalski"); }