@Test
public void dropIndexTest() throws ExecutionException, UnsupportedException {

    IndexMetadataBuilder indexMetadataBuilder = new IndexMetadataBuilder(DB_NAME, TABLE_NAME, INDEX_NAME,
                    IndexType.DEFAULT);
    indexMetadataBuilder.addColumn(COLUMN_NAME, new ColumnType(DataType.VARCHAR));
    indexMetadataBuilder.addColumn(COLUMN_NAME2, new ColumnType(DataType.INT));
    IndexMetadata indexMetadata = indexMetadataBuilder.build();
    DBCollection collection = mock(DBCollection.class);
    when(client.getDB(DB_NAME)).thenReturn(database);
    when(database.getCollection(TABLE_NAME)).thenReturn(collection);
    PowerMockito.mockStatic(IndexUtils.class);
    mongoMetadataEngine.dropIndex(indexMetadata, connection);
    PowerMockito.verifyStatic(Mockito.never());
    IndexUtils.dropIndexWithDefaultName(indexMetadata, database);
    verify(client, times(1)).getDB(DB_NAME);
    verify(collection, times(1)).dropIndex(INDEX_NAME);
}