}

    // Happy path and edge: server encryption key can be non-null, empty, or null
    @Test
    @DisplayName("getServerEncryptionKey returns expected bytes")
    void serverEncryptionKey_variants() {
        byte[] key = new byte[] { 1, 2, 3 };
        when(transport.getServerEncryptionKey()).thenReturn(key);
        assertArrayEquals(key, transport.getServerEncryptionKey());