assertTrue(connection instanceof NtlmHttpURLConnection, "Should use cached handler and wrap it.");
    }

    @Test
    void testOpenConnection_CachedHandler_ReusesExistingHandler() throws Exception {
        // This test verifies that once a handler is cached, subsequent calls reuse it.
        setupMockProtocolHandlers();
        URL url1 = new URL("http://example.com/resource1");