lang/java/reef-applications/reef-vortex/src/test/java/org/apache/reef/vortex/driver/SchedulingPolicyTest.java

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 * Licensed to the Apache Software Foundation (ASF) under one
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 * 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
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 */
package org.apache.reef.vortex.driver;

import org.junit.Test;

import java.util.ArrayDeque;
import java.util.Deque;

import static org.junit.Assert.*;

/**
 * Test SchedulingPolicy.
 */
public class SchedulingPolicyTest {
  private final TestUtil testUtil = new TestUtil();

  /**
   * Test common traits of different scheduling policies.
   */
  @Test
  public void testCommon() throws Exception {
    commonPolicyTests(new RandomSchedulingPolicy());
    commonPolicyTests(new FirstFitSchedulingPolicy(10));
  }

  /**
   * Test FirstFitSchedulingPolicy without preemption events.
   */
  @Test
  public void testFirstFitNoPreemption() throws Exception {
    final int workerCapacity = 1;
    final int numOfWorkers = 5;
    final FirstFitSchedulingPolicy policy = new FirstFitSchedulingPolicy(workerCapacity);

    // Add workers
    final Deque<VortexWorkerManager> workers = new ArrayDeque<>();
    for (int i = 0; i < numOfWorkers; i++) {
      final VortexWorkerManager worker = testUtil.newWorker();
      workers.addFirst(worker);
      policy.workerAdded(worker);
    }

    // Launch 1 tasklet per worker
    for (final VortexWorkerManager worker : workers) {
      final Tasklet tasklet = testUtil.newTasklet();
      assertEquals("This should be the first fit", worker.getId(), policy.trySchedule(tasklet).get());
      policy.taskletLaunched(worker, tasklet);
    }

    // When all workers are full...
    assertFalse("All workers should be full", policy.trySchedule(testUtil.newTasklet()).isPresent());
  }

  /**
   * Test FirstFitSchedulingPolicy with preemption events.
   */
  @Test
  public void testFirstFitPreemptions() throws Exception {
    final int workerCapacity = 1;
    final int numOfWorkers = 10;
    final FirstFitSchedulingPolicy policy = new FirstFitSchedulingPolicy(workerCapacity);

    // Add workers and make the odd ones full
    final ArrayDeque<VortexWorkerManager> evenWorkers = new ArrayDeque<>();
    for (int i = 0; i < numOfWorkers; i++) {
      final VortexWorkerManager worker = testUtil.newWorker();
      policy.workerAdded(worker);

      if (i % 2 == 1) {
        policy.taskletLaunched(worker, testUtil.newTasklet());
      } else {
        evenWorkers.addFirst(worker);
      }
    }

    // Check whether the policy returns even ones in order
    for (final VortexWorkerManager worker : evenWorkers) {
      final Tasklet tasklet = testUtil.newTasklet();
      assertEquals("This should be the first fit", worker.getId(), policy.trySchedule(tasklet).get());
      policy.taskletLaunched(worker, tasklet);
    }

    // When all workers are full...
    assertFalse("All workers should be full", policy.trySchedule(testUtil.newTasklet()).isPresent());
  }

  /**
   * Simple common tests.
   */
  private void commonPolicyTests(final SchedulingPolicy policy) {
    // Initial state
    assertFalse("No worker added yet", policy.trySchedule(testUtil.newTasklet()).isPresent());

    // One worker added
    final VortexWorkerManager worker = testUtil.newWorker();
    policy.workerAdded(worker);
    assertEquals("Only one worker exists", worker.getId(), policy.trySchedule(testUtil.newTasklet()).get());

    // One worker removed
    policy.workerRemoved(worker);
    assertFalse("No worker exists", policy.trySchedule(testUtil.newTasklet()).isPresent());
  }
}