trait RandomGeneratorTrait

trait RandomGeneratorTrait {
    
    /**
     * The random generator.
     *
     * @var \Drupal\Component\Utility\Random
     */
    protected $randomGenerator;
    
    /**
     * Generates a pseudo-random string of ASCII characters of codes 32 to 126.
     *
     * Do not use this method when special characters are not possible (e.g., in
     * machine or file names that have already been validated); instead, use
     * \Drupal\simpletest\TestBase::randomMachineName(). If $length is greater
     * than 3 the random string will include at least one ampersand ('&') and
     * at least one greater than ('>') character to ensure coverage for special
     * characters and avoid the introduction of random test failures.
     *
     * @param int $length
     *   Length of random string to generate.
     *
     * @return string
     *   Pseudo-randomly generated unique string including special characters.
     *
     * @see \Drupal\Component\Utility\Random::string()
     */
    public function randomString($length = 8) {
        if ($length < 4) {
            return $this->getRandomGenerator()
                ->string($length, TRUE, [
                $this,
                'randomStringValidate',
            ]);
        }
        // To prevent the introduction of random test failures, ensure that the
        // returned string contains a character that needs to be escaped in HTML by
        // injecting an ampersand into it.
        $replacement_pos = floor($length / 2);
        // Remove 2 from the length to account for the ampersand and greater than
        // characters.
        $string = $this->getRandomGenerator()
            ->string($length - 2, TRUE, [
            $this,
            'randomStringValidate',
        ]);
        return substr_replace($string, '>&', $replacement_pos, 0);
    }
    
    /**
     * Callback for random string validation.
     *
     * @see \Drupal\Component\Utility\Random::string()
     *
     * @param string $string
     *   The random string to validate.
     *
     * @return bool
     *   TRUE if the random string is valid, FALSE if not.
     */
    public function randomStringValidate($string) {
        // Consecutive spaces causes issues for
        // \Drupal\simpletest\WebTestBase::assertLink().
        if (preg_match('/\\s{2,}/', $string)) {
            return FALSE;
        }
        // Starting or ending with a space means that length might not be what is
        // expected.
        if (preg_match('/^\\s|\\s$/', $string)) {
            return FALSE;
        }
        return TRUE;
    }
    
    /**
     * Generates a unique random string containing letters and numbers.
     *
     * Do not use this method when testing unvalidated user input. Instead, use
     * \Drupal\simpletest\TestBase::randomString().
     *
     * @param int $length
     *   Length of random string to generate.
     *
     * @return string
     *   Randomly generated unique string.
     *
     * @see \Drupal\Component\Utility\Random::name()
     */
    protected function randomMachineName($length = 8) {
        return $this->getRandomGenerator()
            ->name($length, TRUE);
    }
    
    /**
     * Generates a random PHP object.
     *
     * @param int $size
     *   The number of random keys to add to the object.
     *
     * @return object
     *   The generated object, with the specified number of random keys. Each key
     *   has a random string value.
     *
     * @see \Drupal\Component\Utility\Random::object()
     */
    public function randomObject($size = 4) {
        return $this->getRandomGenerator()
            ->object($size);
    }
    
    /**
     * Gets the random generator for the utility methods.
     *
     * @return \Drupal\Component\Utility\Random
     *   The random generator.
     */
    protected function getRandomGenerator() {
        if (!is_object($this->randomGenerator)) {
            $this->randomGenerator = new Random();
        }
        return $this->randomGenerator;
    }

}