Mapreduce（7）----单元测试

1.MRUnit

使用MRUnit框架进行单元测试，该框架对不同的测试对象使用不同的Driver，因此分为了：MapDriver、ReduceDriver和MapReduceDriver。

2. 代码：

(1)主要的包：

import org.apache.hadoop.mrunit.mapreduce.MapDriver;
import org.apache.hadoop.mrunit.mapreduce.ReduceDriver;
import org.junit.Rule;
import org.junit.Test;

　（2）代码主要部分：

public class MRJobTest {
  private MapDriver<LongWritable,Text, Text, Text> mapDriver =
      MapDriver.newMapDriver(new MRJob.MRJobMapper());
  private ReduceDriver<Text, Text, Text, Text> reduceDriver = ReduceDriver.newReduceDriver(new MRJob.MRJobReducer());

  @Test
  public void testMap() throws IOException {
    mapDriver.addInput(new LongWritable(), new Text(
        "2	4	101,10")); //输入数据
    mapDriver.addInput(new LongWritable(), new Text(
        "3	5"));
    mapDriver.addInput(new LongWritable(), new Text(
        ""));
    assertEquals(7,mapDriver.run().size());  //执行map代码

  }

  @Test
  public void testReducer() throws IOException {
    reduceDriver.addInput(new Text("1"), Lists.newArrayList(new Text("101"), new Text("101"), new Text("303")));  //输入reduce数据
    reduceDriver.addInput(new Text("3"), Lists.newArrayList(new Text("101"), new Text("202"), new Text("303")));

    assertEquals(3, reduceDriver.run().size());  //执行reduce.run代码
    assertEquals("Expected 2 counter increment", 2, reduceDriver.getCounters()
        .findCounter(MRJob.MRJobCounter.LOW5).getValue());  //获取reduce中的自定义枚举名为MRJobCounter.LOW5的counter

} }