/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.hive.contrib.mr;
import java.io.StringReader;
import java.io.StringWriter;
import java.util.Iterator;
import java.util.NoSuchElementException;
import junit.framework.TestCase;
import org.apache.hadoop.util.Shell;
/**
* TestGenericMR.
*
*/
public final class TestGenericMR extends TestCase {
public void testReduceTooFar() throws Exception {
try {
new GenericMR().reduce(new StringReader("a\tb\tc"), new StringWriter(),
new Reducer() {
public void reduce(String key, Iterator<String[]> records,
Output output) throws Exception {
while (true) {
records.next();
}
}
});
} catch (final NoSuchElementException nsee) {
// expected
return;
}
fail("Expected NoSuchElementException");
}
public void testEmptyMap() throws Exception {
final StringWriter out = new StringWriter();
new GenericMR().map(new StringReader(""), out, identityMapper());
assertEquals(0, out.toString().length());
}
public void testIdentityMap() throws Exception {
final String in = "a\tb\nc\td";
final StringWriter out = new StringWriter();
new GenericMR().map(new StringReader(in), out, identityMapper());
assertEquals(in + "\n", out.toString());
}
public void testKVSplitMap() throws Exception {
final String in = "k1=v1,k2=v2\nk1=v2,k2=v3";
final String expected = "k1\tv1\nk2\tv2\nk1\tv2\nk2\tv3\n";
final StringWriter out = new StringWriter();
new GenericMR().map(new StringReader(in), out, new Mapper() {
public void map(String[] record, Output output) throws Exception {
for (final String kvs : record[0].split(",")) {
final String[] kv = kvs.split("=");
output.collect(new String[] {kv[0], kv[1]});
}
}
});
assertEquals(expected, out.toString());
}
public void testIdentityReduce() throws Exception {
final String in = "a\tb\nc\td";
final StringWriter out = new StringWriter();
new GenericMR().reduce(new StringReader(in), out, identityReducer());
assertEquals(in + "\n", out.toString());
}
public void testWordCountReduce() throws Exception {
final String in = "hello\t1\nhello\t2\nokay\t4\nokay\t6\nokay\t2";
final StringWriter out = new StringWriter();
new GenericMR().reduce(new StringReader(in), out, new Reducer() {
@Override
public void reduce(String key, Iterator<String[]> records, Output output)
throws Exception {
int count = 0;
while (records.hasNext()) {
count += Integer.parseInt(records.next()[1]);
}
output.collect(new String[] {key, String.valueOf(count)});
}
});
final String expected = "hello\t3\nokay\t12\n";
assertEquals(expected, out.toString());
}
private Mapper identityMapper() {
return new Mapper() {
@Override
public void map(String[] record, Output output) throws Exception {
output.collect(record);
}
};
}
private Reducer identityReducer() {
return new Reducer() {
@Override
public void reduce(String key, Iterator<String[]> records, Output output)
throws Exception {
while (records.hasNext()) {
output.collect(records.next());
}
}
};
}
}