package jcgp.tests;

import static org.junit.Assert.assertTrue;
import jcgp.JCGP.Resources;
import jcgp.population.Chromosome;
import jcgp.population.Population;

import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;

/**
 * 
 * Tests which cover the behaviour specified for a population.
 * 
 *  - It should be possible to iterate through all the chromosomes in a population.
 *  - When constructed with no arguments, it should generate populationSize
 *    random chromosomes, distributed according to the EA parameters.
 *  - If one or more chromosomes are passed into the constructor, it should use them
 *    as parents to create the rest of the population.
 *  
 * 
 * @author Eduardo Pedroni
 *
 */
public class PopulationTests {

	private Population population;
	private static Resources resources;

	@BeforeClass
	public static void setUpBeforeClass() throws Exception {
		resources = new Resources();
		
		
//		// initialise function set
//		FunctionSet functionSet = new FunctionSet(new Arithmetic.Addition(), new Arithmetic.Subtraction());
//
//		// initialise utilities
//		Utilities.setResources(new Random(1234), functionSet);
//
//		// initialise parameters
//		Resources.setColumns(20);
//		Resources.setRows(20);
//		Resources.setInputs(2);
//		Resources.setOutputs(4);
//		Resources.setLevelsBack(1);
//		Resources.setMutationRate(10);
//		Resources.setTotalGenerations(100);
//		Resources.setTotalRuns(5);
//		Resources.setPopulationSize(1, 4);
//		Resources.setMaxArity(functionSet.getMaxArity());
	}

	@Before
	public void setUp() throws Exception {
		population = new Population(resources);
	}

	@Test
	public void defaultPopulationTest() {
		// check that the constructor really generates populationSize chromosomes when none is given
		int chromosomes = 0;
		while (true) {
			try {
				population.getChromosome(chromosomes);
			} catch (IndexOutOfBoundsException e) {
				break;
			}
			chromosomes++;
		}

		assertTrue("Incorrect number of chromosomes generated.", chromosomes == (int) resources.get("popSize"));
	}
	
	@Test
	public void preinitialisedChromosomeTest() {
		// the original chromosome that will be cloned
		Chromosome oc = new Chromosome(resources);

		// initialise a population with a copy of it
		population = new Population(oc, resources);
		// check that the first parent chromosome is identical to, but not the same instance as, the one given
		assertTrue("Incorrect chromosome in population.", population.getChromosome(0).compareTo(oc) && population.getChromosome(0) != oc);
	}
}