?????????????????У?????????map??org.apache.hadoop.mapred.lib.IdentityMapper????????????????map?????????????????????

????org.apache.hadoop.mrunit.MapDriver???????MRUnit????е?????????????????map????

???????????withInput????????????????withOutput????????????????????????runTest?????????????

????????

????1. ????Map????????????MapDriver??

????2. ????Reduce????????????ReduceDriver??

????3. ?????????????MapReduce????????????MapReduceDriver??

????4. ??????MapReduce??????????????????????PipelineMapReduceDriver??

???????

????MRUnit???????????????????????????JUnit??

?????????????д??MapReduce?????а????????OutputCollector?????????MRUnit???????????Mock??????????OutputCollector???????

????????

??????????MRUnit???????????????

????1. ?????MapReduce????е?????????????????Map??????????shuffle???????????Reduce?????

????2. ?????Streaming????MapReduce??????

???????MRUnit????Щ??????????????????????????