Method test

/**
 * Method to test the value.
 *
 * @param   \SimpleXMLElement  $element  The SimpleXMLElement object representing the `<field>` tag for the form field object.
 * @param   mixed              $value    The form field value to validate.
 * @param   string             $group    The field name group control value. This acts as as an array container for the field.
 *                                       For example if the field has name="foo" and the group value is set to "bar" then the
 *                                       full field name would end up being "bar[foo]".
 * @param   Registry           $input    An optional Registry object with the entire data set to validate against the entire form.
 * @param   Form               $form     The form object for which the field is being tested.
 *
 * @return  boolean  True if the value is valid, false otherwise.
 *
 * @since   1.6
 * @throws  \UnexpectedValueException if rule is invalid.
 */
public function test(\SimpleXMLElement $element, $value, $group = null, Registry $input = null, Form $form = null)
{
    // Check for a valid regex.
    if (empty($this->regex)) {
        throw new \UnexpectedValueException(sprintf('%s has invalid regex.', \get_class($this)));
    }
    // Add unicode property support if available.
    if (JCOMPAT_UNICODE_PROPERTIES) {
        $this->modifiers = strpos($this->modifiers, 'u') !== false ? $this->modifiers : $this->modifiers . 'u';
    }
    // Test the value against the regular expression.
    if (preg_match(\chr(1) . $this->regex . \chr(1) . $this->modifiers, $value)) {
        return true;
    }
    return false;
}