// Copyright 2016 Twitter. All rights reserved.
//
// Licensed 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 com.twitter.heron.simulator.grouping;
import java.util.LinkedList;
import java.util.List;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import com.twitter.heron.proto.system.HeronTuples;
public class ShuffleGroupingTest {
@Before
public void before() throws Exception {
}
@After
public void after() throws Exception {
}
/**
* Method: test round robin nature of shuffle grouping
*/
@Test
public void testRoundRobin() throws Exception {
List<Integer> taskIds = new LinkedList<>();
taskIds.add(0);
taskIds.add(2);
taskIds.add(4);
taskIds.add(8);
ShuffleGrouping g = new ShuffleGrouping(taskIds);
HeronTuples.HeronDataTuple dummy = HeronTuples.HeronDataTuple.getDefaultInstance();
List<Integer> dest = g.getListToSend(dummy);
Assert.assertEquals(dest.size(), 1);
int first = dest.get(0);
int index = -1;
for (int i = 0; i < taskIds.size(); ++i) {
if (taskIds.get(i) == first) {
index = i;
break;
}
}
dest.clear();
for (int i = 0; i < 100; ++i) {
dest = g.getListToSend(dummy);
Assert.assertEquals(dest.size(), 1);
int d = dest.get(0);
index = (index + 1) % taskIds.size();
Assert.assertEquals((Integer) d, taskIds.get(index));
dest.clear();
}
}
/**
* Method: test random start
*/
@Test
public void testRandomStart() throws Exception {
List<Integer> taskIds = new LinkedList<>();
taskIds.add(0);
taskIds.add(1);
int zeros = 0;
int ones = 0;
int count = 1000;
for (int i = 0; i < count; ++i) {
ShuffleGrouping g = new ShuffleGrouping(taskIds);
HeronTuples.HeronDataTuple dummy = HeronTuples.HeronDataTuple.getDefaultInstance();
List<Integer> dest = g.getListToSend(dummy);
Assert.assertEquals(dest.size(), 1);
int first = dest.get(0);
if (first == 0) {
zeros++;
} else {
ones++;
}
dest.clear();
}
double variance = ((double) Math.abs(zeros - ones)) / count;
Assert.assertTrue(variance <= 0.1);
}
}