assertNull(source.getTitle());
        assertNull(source.getUrl());
        assertNull(source.getDocId());
        assertNull(source.getSnippet());
    }

    @Test
    public void test_chatSourceFromMap() {
        final Map<String, Object> doc = new HashMap<>();
        doc.put("title", "Test Title");
        doc.put("url", "https://example.com");
        doc.put("doc_id", "doc-123");