}

    /**
     * Manually unblock an IP
     *
     * @param sourceIp the IP to unblock
     * @return true if IP was unblocked, false if not found
     */
    public boolean unblockIp(String sourceIp) {
        IpAttempts ip = ipAttempts.get(sourceIp);
        if (ip != null) {
            ip.reset();
            log.info("Manually unblocked IP: {}", sourceIp);
            return true;
        }

        assertFalse(rateLimiter.checkAttempt("user6", ip), "IP should be blocked");

        // Manually unblock
        assertTrue(rateLimiter.unblockIp(ip), "Manual unblock should succeed");

        // Should be allowed again
        assertTrue(rateLimiter.checkAttempt("user7", ip), "Should be allowed after manual unblock");
    }

    @Test
    public void testNullUsername() throws Exception {