### Question:
DetailResultQuery extends AbstractDetailResultQuery { @Override public DetailQueryResultSet merge(List<DetailQueryResultSet> resultSets) { return new MergeDetailQueryResultSet(fetchSize, resultSets); } DetailResultQuery(int fetchSize, List<Query<DetailQueryResultSet>> queries);  DetailResultQuery(int fetchSize, List<Query<DetailQueryResultSet>> queries, List<DetailTarget> targets); @Override DetailQueryResultSet merge(List<DetailQueryResultSet> resultSets);  }### Answer:
@Test public void merge() throws Exception { List queries = mock(List.class); List resultsets = mock(List.class); int fetchSize = mock(Integer.class); MergeDetailQueryResultSet mergeDetailQueryResultSet = mock(MergeDetailQueryResultSet.class); whenNew(MergeDetailQueryResultSet.class).withArguments(fetchSize, resultsets).thenReturn(mergeDetailQueryResultSet); assertEquals(mergeDetailQueryResultSet, new DetailResultQuery(fetchSize, queries).merge(resultsets)); }