package lab.art;

import static org.junit.Assert.*;

import java.util.Random;

import org.junit.Test;

public class AverageTester 
{
    @Test
    public void testConstructor() 
    {
	final int NUMBER =10;

	Expression expression = new VariableX();
	Expression second = new VariableX();
	for (int n = 0; n < NUMBER; n++)
	{
	    expression = new Average(expression, second);
	}
    }
    
    @Test
    public void testEvaluate() 
    {
	Random random = new Random(System.currentTimeMillis());

	int NUMBER = 10;
	double DELTA = 0.0001;
	for (int n = 0; n < NUMBER; n++)
	{
	    Expression expression = new VariableX();
	    Expression second = new VariableY();
		
	    double x = random.nextDouble();
	    if (random.nextBoolean())
	    {
		x = -x;
	    }
	    double y = random.nextDouble();
	    if (random.nextBoolean())
	    {
		y = -y;
	    }

	    double value = x;
	    for (int m = 0; m < NUMBER; m++)
	    {
		expression = new Average(expression, second);
		value = (value + y) / 2;
		assertEquals("evaluate method failed", value, expression.evaluate(x, y), DELTA);
	    }
	}
    }
    
    @Test
    public void testToString() 
    {
	Expression expression = new VariableX();
	Expression second = new VariableY();
	String representation = "x";
	
	int NUMBER = 10;
	for (int n = 0; n < NUMBER; n++)
	{
	    expression = new Average(expression, second);
	    representation = "average(" + representation + ", y)";
	    assertEquals("toString method failed", representation, expression.toString());
	}
    }
}