/**
    * Copyright (c) 2009, The JUNG Authors 
    *
    * All rights reserved.
    *
    * This software is open-source under the BSD license; see either
    * "license.txt" or
    * https://github.com/jrtom/jung/blob/master/LICENSE for a description.
    * Created on Jan 13, 2009
   * 
   */
  package edu.uci.ics.jung.algorithms.util;
  
  import java.util.HashMap;
  import java.util.Map;
  
  import junit.framework.TestCase;
  
  /**
   * @author jrtom
   *
   */
  public class TestWeightedChoice extends TestCase 
  {
  	private WeightedChoice<String> weighted_choice;
  	private Map<String, Double> item_weights = new HashMap<String, Double>();
  	private Map<String, Integer> item_counts = new HashMap<String, Integer>();
  	
  	@Override
      public void tearDown()
  	{
  		item_weights.clear();
  		item_counts.clear();
  	}
  
  	private void initializeWeights(double[] weights)
  	{
  		item_weights.put("a", weights[0]);
  		item_weights.put("b", weights[1]);
  		item_weights.put("c", weights[2]);
  		item_weights.put("d", weights[3]);
  		
  		for (String key : item_weights.keySet())
  			item_counts.put(key, 0);
  
  	}
  
  	private void runWeightedChoice()
  	{
  		weighted_choice = new WeightedChoice<String>(item_weights, new NotRandom(100));
  		
  		int max_iterations = 10000;
  		for (int i = 0; i < max_iterations; i++)
  		{
  			String item = weighted_choice.nextItem();
  			int count = item_counts.get(item);
  			item_counts.put(item, count+1);
  		}
  		
  		for (String key : item_weights.keySet())
  			assertEquals((int)(item_weights.get(key) * max_iterations), 
  						item_counts.get(key).intValue());
  	}
  	
  	public void testUniform() 
  	{
  		initializeWeights(new double[]{0.25, 0.25, 0.25, 0.25});
  		
  		runWeightedChoice();
  	}
  	
  	public void testNonUniform()
  	{
  		initializeWeights(new double[]{0.45, 0.10, 0.13, 0.32});
  		
  		runWeightedChoice();
  	}
  }