<?php

class DataSetValue
{
	const ALPHA_LOWER   = 'abcdefghijklmnopqrstuvwxyz';
	const ALPHA_NUMERIC = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
	/* more constants */

	public function __construct($data = self::ALPHA_NUMERIC, $dataLength = 62)
	{
		$this->setData($data)
		     ->setDataLength($dataLength);
	}

	/* getters and setters */

	public function __toString()
	{
		// e.g. echo new DataSetValue(DataSetValue::ALPHA_LOWER, 2) would output "ab"
		return substr($this->getData(), 0, $this->getDataLength());
	}
}

class AssertionTuple
{
	protected $assertionMethod = '';
	protected $data;	

	public function __construct($assertionMethod, DataSetValue $data)
	{
		$this->setAssertionMethod($assertionMethod)
		     ->setData($data);
	}
}

class AssertionStack implements Iterator
{
	private   $position = 0;
	protected $stack    = array();
	
	public function push(AssertionTuple $tuple)
	{
		$this->stack[] = $tuple;
	}

	public function rewind() {
		$this->position = 0;
	}

	public function current() {
		return $this->stack[$this->position]->getData();
	}

	public function key() {
		return $this->stack[$this->position]->getAssertionMethod();
	}

	public function next() {
		++$this->position;
	}

	public function valid() {
		return isset($this->stack[$this->position]);
	}
}

class UnitTest extends PHPUnit_Framework_TestCase
{
	public function testAddress1()
	{
		$stack = new AssertionStack;
		$stack->push(new AssertionTuple('equals', new DataSetValue(DataSetValue::ALPHA_NUMERIC)))
		      ->push(new AssertionTuple('notEquals', new DataSetValue(DataSetValue::SYMBOLS)));

		foreach ($stack as $assertionMethod => $data)
		{
			$this->instance->setAddress2($data);

			$assertionMethod = 'assert' . ucfirst($assertionMethod);
			$this->$assertionMethod($data, $this->instance->getAddress2());
		}
}