}

    // Getters and setters

    /**
     * Gets the last heartbeat timestamp.
     *
     * @return the last heartbeat timestamp in milliseconds
     */
    public long getLastHeartbeat() {
        return lastHeartbeat;
    }

    /**
     * Gets the registration ID.
     *
     * @return the registration ID
     */
    public String getRegistrationId() {

        long initialTime = registration.getLastHeartbeat();

        Thread.sleep(50); // Ensure sufficient time difference
        registration.updateHeartbeat();

        // After update, should not be expired with long timeout
        assertFalse(registration.isExpired(60000));

        // Verify heartbeat was actually updated
        assertTrue(registration.getLastHeartbeat() > initialTime);
    }

    @Test