Assert\Assertion::contains PHP Method

    public static function contains($string, $needle, $message = null, $propertyPath = null, $encoding = 'utf8')
    {
        static::string($string, $message, $propertyPath);
        if (mb_strpos($string, $needle, null, $encoding) === false) {
            $message = sprintf($message ?: 'Value "%s" does not contain "%s".', static::stringify($string), static::stringify($needle));
            $constraints = array('needle' => $needle, 'encoding' => $encoding);
            throw static::createException($string, $message, static::INVALID_STRING_CONTAINS, $propertyPath, $constraints);
        }
        return true;
    }

 /**
  * @Then I should see the logging messages
  */
 public function iShouldSeeTheLoggingMessages()
 {
     $display = $this->display;
     Assertion::contains($display, 'purging database');
     Assertion::contains($display, 'AppBundle\\DataFixtures\\ORM\\RoleFixture');
     Assertion::contains($display, 'AppBundle\\DataFixtures\\ORM\\AdminFixture');
 }