PHP Username Generator Using the Template Pattern

TemplateUsernameGenerator.php

abstract class UsernameGenerator {
  private $user;
  
  abstract function generateUsername();
  public function getUsername($user) {
    $this->user = strtolower($user);
	
	return $this->generateUsername();
  }
  protected function getFirstName() {
  	$parts = (explode(' ', $this->user, 2));
  	return $parts[0];
  }
  protected function getLastName() {
  	$parts = (explode(' ', $this->user, 2));
  	return $parts[1];  
  }  
  protected function getFirstLetter($string) {
  	return substr($string, 0, 1);
  }
  protected function getFirstVowel($string) {
  	$position = strcspn(strtolower($string), "aeiou");
	if($position>0) return substr($string, $position, 1);
  }
}

class UsernameGenerator1 extends UsernameGenerator {
  public function generateUsername() {
  	$username = "";
	$username .= $this->getFirstLetter($this->getFirstName());
	$username .= $this->getFirstLetter($this->getLastName());
	$username .= $this->getFirstVowel($this->getLastName());
	return $username;
  }
}

$tests = array("Pez Cuckow" => "pcu", "Oliver Brown" => "obo", "Alpha Alpha" => "aa");

$generator = new UsernameGenerator1();
foreach($tests as $input => $expectedOutput) {
	$output = $generator->getUsername($input);
	echo sprintf("%s: %s\t%s\n", $input, $output,
               ($output == $expectedOutput ? "PASS" : "FAIL\tExpected $expectedOutput"));
}