public function done()
    {
        if (array_diff($this->registered, $this->serviceProvider->provides())) {
            throw new ServiceProviderException(
                get_class($this->serviceProvider) . ' said it would provide: "' .
                join(', ', $this->serviceProvider->provides()) . '" but ended up providing "' .
                join(', ', $this->registered) . '"'
            );
        }
    }