### Question:
DefaultAtlasCombineStrategy implements AtlasCombineStrategy { @Override public String combineValues(Map<Integer, String> values) { return combineValues(values, getDelimiter(), getLimit()); }  @Override StringDelimiter getDelimiter(); @Override void setDelimiter(StringDelimiter delimiter); @Override Integer getLimit(); @Override void setLimit(Integer limit); boolean isDisableAutoTrim(); void setDisableAutoTrim(boolean disableAutoTrim); boolean isDisableAddDelimiterOnNull(); void setDisableAddDelimiterOnNull(boolean disableAddDelimiterOnNull); @Override String combineValues(Map<Integer, String> values); @Override String combineValues(Map<Integer, String> values, StringDelimiter delimiter); @Override String combineValues(Map<Integer, String> values, StringDelimiter delimiter, Integer limit); @Override String combineValues(Map<Integer, String> values, String delimiter); static final StringDelimiter DEFAULT_COMBINE_DELIMITER; static final Integer DEFAULT_COMBINE_LIMIT; }### Answer:
@Test public void testCombineSingleValue() { assertNotNull(combine); String value = combine.combineValues(generateCombineMap(1)); assertNotNull(value); assertEquals("a", value); }
@Test public void testCombineValues() { assertNotNull(combine); String value = combine.combineValues(generateCombineMap(6)); assertNotNull(value); assertEquals("a b c d e f", value); }
@Test public void testSeparateValuesNullValue() { assertNotNull(combine); String value = combine.combineValues(null); assertNull(value); }
@Test public void testCombineValuesEmptyValue() { assertNotNull(combine); String value = combine.combineValues(new HashMap<Integer, String>()); assertNull(value); }