Hadoop MapReduce marco a través de pruebas de ensayo MRUnit

1. La introducción de marco de pruebas MRUnit: pom.xml:

		<!-- https://mvnrepository.com/artifact/org.apache.mrunit/mrunit MRUnit测试 -->
		<dependency>
			<groupId>org.apache.mrunit</groupId>
			<artifactId>mrunit</artifactId>
			<version>0.9.0-incubating</version>
			<classifier>hadoop2</classifier>
			<scope>test</scope>
		</dependency>

2. Escribir una clase de prueba

public class TestReducer {

	// 用于测试Reduce

	@Test
	public void TestMethod() {

		ReduceDriver<Text, IntWritable, Text, IntWritable> reduceDriver = new ReduceDriver<Text, IntWritable, Text, IntWritable>();
		
		//设置要测试对像
		reduceDriver.withReducer(new MaxReduce());
		
		// 设置测试的key=1950
		reduceDriver.withInputKey(new Text("1950"));
		
		// 设置测试的values=[ 10,13,0]
		reduceDriver.withInputValues(Arrays.asList(new IntWritable(10), new IntWritable(13), new IntWritable(0)));
		
		//设置预期输出结果
		reduceDriver.withOutput(new Text("1950"), new IntWritable(134));
		
		//执行测试
		reduceDriver.runTest();

	}

}
//要测试的程序
class MaxReduce extends Reducer<Text, IntWritable, Text, IntWritable> {

	@Override
	protected void reduce(Text key, Iterable<IntWritable> values,
			Reducer<Text, IntWritable, Text, IntWritable>.Context context) throws IOException, InterruptedException {
		int maxValue = Integer.MIN_VALUE;

		for (IntWritable value : values) {
			maxValue = Math.max(maxValue, value.get());
		}

		context.write(key, new IntWritable(maxValue));

	}

}