/*
 * 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.samoa.topology.impl;

import static org.junit.Assert.*;
import mockit.Mocked;
import mockit.Verifications;

import org.apache.samoa.topology.impl.ThreadsEngine;
import org.apache.samoa.topology.impl.ThreadsTopology;
import org.junit.After;
import org.junit.Test;

/**
 * @author Anh Thu Vu
 * 
 */
public class ThreadsEngineTest {

  @Mocked
  ThreadsTopology topology;

  private final int numThreads = 4;
  private final int numThreadsSmaller = 3;
  private final int numThreadsLarger = 5;

  @After
  public void cleanup() {
    ThreadsEngine.clearThreadPool();
  }

  @Test
  public void testSetNumberOfThreadsSimple() {
    ThreadsEngine.setNumberOfThreads(numThreads);
    assertEquals("Number of threads is not set correctly.", numThreads,
        ThreadsEngine.getNumberOfThreads(), 0);
  }

  @Test
  public void testSetNumberOfThreadsRepeat() {
    ThreadsEngine.setNumberOfThreads(numThreads);
    ThreadsEngine.setNumberOfThreads(numThreads);
    assertEquals("Number of threads is not set correctly.", numThreads,
        ThreadsEngine.getNumberOfThreads(), 0);
  }

  @Test
  public void testSetNumberOfThreadsIncrease() {
    ThreadsEngine.setNumberOfThreads(numThreads);
    ThreadsEngine.setNumberOfThreads(numThreadsLarger);
    assertEquals("Number of threads is not set correctly.", numThreadsLarger,
        ThreadsEngine.getNumberOfThreads(), 0);
  }

  @Test(expected = IllegalStateException.class)
  public void testSetNumberOfThreadsDecrease() {
    ThreadsEngine.setNumberOfThreads(numThreads);
    ThreadsEngine.setNumberOfThreads(numThreadsSmaller);
    // Exception expected
  }

  @Test(expected = IllegalStateException.class)
  public void testSetNumberOfThreadsNegative() {
    ThreadsEngine.setNumberOfThreads(-1);
    // Exception expected
  }

  @Test(expected = IllegalStateException.class)
  public void testSetNumberOfThreadsZero() {
    ThreadsEngine.setNumberOfThreads(0);
    // Exception expected
  }

  @Test
  public void testClearThreadPool() {
    ThreadsEngine.setNumberOfThreads(numThreads);
    ThreadsEngine.clearThreadPool();
    assertEquals("ThreadsEngine was not shutdown properly.", 0, ThreadsEngine.getNumberOfThreads());
  }

  @Test
  public void testGetThreadWithIndexWithinPoolSize() {
    ThreadsEngine.setNumberOfThreads(numThreads);
    for (int i = 0; i < numThreads; i++) {
      assertNotNull("ExecutorService is not initialized correctly.", ThreadsEngine.getThreadWithIndex(i));
    }
  }

  @Test
  public void testGetThreadWithIndexOutOfPoolSize() {
    ThreadsEngine.setNumberOfThreads(numThreads);
    for (int i = 0; i < numThreads + 3; i++) {
      assertNotNull("ExecutorService is not initialized correctly.", ThreadsEngine.getThreadWithIndex(i));
    }
  }

  @Test(expected = IllegalStateException.class)
  public void testGetThreadWithIndexFromEmptyPool() {
    for (int i = 0; i < numThreads; i++) {
      ThreadsEngine.getThreadWithIndex(i);
    }
  }

  @Test
  public void testSubmitTopology() {
    ThreadsEngine.submitTopology(topology, numThreads);
    new Verifications() {
      {
        topology.run();
        times = 1;
      }
    };
    assertEquals("Number of threads is not set correctly.", numThreads,
        ThreadsEngine.getNumberOfThreads(), 0);
  }

}