How to do Mapper testing using MRUnit Test?

Question

I am new to Hadoop. I want to test my mapper part alone using MRUnit Test. I have tried a lot. But i dont know how to solve the following error-
"The method setMapper(Mapper) in the type MapDriver is not applicable for the arguments (Recommand.IdIndexMapper)". I am using Hadoop-1.2.1, Eclipse Juno,mrunit-1.0.0-hadoop1.jar,junit-4.11,mockito-all-1.9.5.jar. Bellow are my code,

My Mapper Class:
Class name: Recommand,

public static class IdIndexMapper extends MapReduceBase implements Mapper<LongWritable, Text, Text, Text>{

        public void map(LongWritable key, Text val, OutputCollector<Text, Text> output,Reporter reporter)throws IOException{
            String[] ids;
            String ln=val.toString();
            ids=ln.split("\t");
            output.collect(new Text(ids[0]),new Text(ids[1]));
   // System.out.println(ids[0]+" "+ids[1]);

    }

My Testing Code:

package org.apache.hadoop.examples;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;



import org.apache.hadoop.classification.InterfaceAudience.Private;
import org.apache.hadoop.classification.InterfaceAudience.Public;
import org.apache.hadoop.examples.WordCount.IntSumReducer;
//import org.apache.hadoop.examples.WordCount.TokenizerMapper;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mrunit.mapreduce.MapDriver;
import org.junit.Before;
import org.junit.Test;
import org.myorg.Recommand.IdIndexMapper;

public class RecomTest {
    MapDriver<LongWritable, Text, Text, Text> mapDriver;

     @Before
     public void setUp() throws Exception {
         IdIndexMapper mapper=new IdIndexMapper();
         mapper.configure(new JobConf());
        mapDriver=new MapDriver<LongWritable, Text, Text,Text>();
        mapDriver.setMapper(mapper);
     }

    @Test
    public void testMapper() throws IOException {

        final LongWritable inputKey = new LongWritable(0);
         final Text inputValue = new Text("M1023    M1024,M1022,M1025");

         final Text outputKey = new Text("M1023");
         final Text outputValue = new Text("M1024,M1022,M1025");

         mapDriver.withInput(inputKey, inputValue);
         mapDriver.withOutput(outputKey, outputValue);
         mapDriver.runTest();



    }

}

Error I got is:

The method setMapper(Mapper) in the type MapDriver is not applicable for the arguments (Recommand.IdIndexMapper)

Can anyone help me to solve this please?

Answer 1

1.0.0 MapDriver.setMapper() expects a org.apache.hadoop.mapred.Mapper. You are using the older org.apache.hadoop.mapreduce.Mapper. They are two different animals. If you want to use MRUnit 0.8.x you can use the old Mapper. You can get 0.8.x here

---

EDIT

I see the real problem. The above is incorrect. There are two MapDrivers - org.apache.hadoop.mrunit.mapreduce.MapDriver(the one you're using) and org.apache.hadoop.mrunit.MapDriver. You should be using the latter MapDriver

Also note that there are two different MRUnits. There's a hadoop1 and hadoop2 version. The latter MapDriver(the one you need) is in the hadoop2. You can get the download here