@Test
public void attachCitationsAndLimitDocs_NO_CITATIONS() {

    
    
    // given
    
    JavaPairRDD<String, MatchableEntity> citIdDocPairs = sparkContext.parallelizePairs(ImmutableList.of(
            new Tuple2<>(citation1.id(), document1),
            new Tuple2<>(citation1.id(), document2),
            new Tuple2<>(citation2.id(), document4)));
    
    JavaPairRDD<String, MatchableEntity> citations = sparkContext.parallelizePairs(Lists.newArrayList());
    
    
    
    // execute
    
    JavaPairRDD<MatchableEntity, MatchableEntity> actualCitDocPairs = citationAttacher.attachCitationsAndLimitDocs(citIdDocPairs, citations);
    
    
    // assert
    
    assertEquals(actualCitDocPairs.count(), 0);
    
}