Parser.php

<?php
namespace Acme;

/**
 * Dummy class
 *
 */
class Parser
{

	public function parse($data) {
		$values = $this->splitValues($data);
		$this->validateMail($values[2]);

		$values[4] = $this->extractGroups($values[4]);

		return $values;
	}

	private function splitValues($data) {
		$values = explode(';', $data);

		foreach($values as &$value) {
			$value = trim($value);
		}
		return $values;		
	}

	private function validateMail($mail){
		if(!filter_var($mail,FILTER_VALIDATE_EMAIL)) {
			throw new \InvalidArgumentException();
		}
	}

	private function extractGroups($component) {
		$matches = array();
		preg_match('/\[(.*)\]/', $component, $matches);
		return explode(',',$matches[1]);		
	}


}

ParserTest.php

<?php

namespace Acme;

/**
 * Description of DummyTest
 *
 */
class ParserTest extends \PHPUnit_Framework_TestCase
{

    public $data;

    public function setUp()
    {

       $this->data = 'juan; pérez peréz; juanperez@ejemplo.com;juan;[contabilidad,dirección]';

    }

    public function testNumeroDeElementosCorrecto() {

      $expected = 5;
      $parser = new \Acme\Parser();
      $values = $parser->parse($this->data);
      $this->assertEquals($expected,count($values));
    }

    public function testComprobarCampos() {
      $expected = array(
        'juan',
        'pérez peréz',
        'juanperez@ejemplo.com',
        'juan',
        array(
          'contabilidad',
          'dirección'
          )
        );
      $parser = new \Acme\Parser();
      $values = $parser->parse($this->data);
      $this->assertEquals($expected,$values);
    }

    /**
      @expectedException \InvalidArgumentException
    */
    public function testValidarTercerCampoCorreoElectronico() {
      $data = 'juan; pérez peréz; juanperezejemplo.com;juan;[contabilidad,dirección]';
      $parser = new \Acme\Parser();
      $parser->parse($data);
      
    }

}