diff --git a/test/test_rag_supplemental_expansion.py b/test/test_rag_supplemental_expansion.py
new file mode 100644
index 0000000..76e44fd
--- /dev/null
+++ b/test/test_rag_supplemental_expansion.py
@@ -0,0 +1,372 @@
+from __future__ import annotations
+
+import sqlite3
+from pathlib import Path
+
+from scripts.rag_supplemental_expansion import (
+    canonical_student_main_path,
+    expand_results_with_supplemental_sources,
+    is_multi_document_query,
+)
+
+
+def create_db(tmp_path: Path) -> Path:
+    db = tmp_path / "supplemental.sqlite"
+
+    with sqlite3.connect(db) as conn:
+        conn.execute(
+            """
+            CREATE TABLE documents (
+                id INTEGER PRIMARY KEY,
+                path TEXT NOT NULL,
+                title TEXT,
+                author TEXT,
+                published INTEGER
+            )
+            """
+        )
+        conn.execute(
+            """
+            CREATE TABLE chunks (
+                id INTEGER PRIMARY KEY,
+                chunk_id TEXT NOT NULL,
+                document_path TEXT NOT NULL,
+                title TEXT,
+                author TEXT,
+                published INTEGER,
+                chunk_index INTEGER,
+                heading_paths_json TEXT,
+                text TEXT
+            )
+            """
+        )
+
+    return db
+
+
+def add_document(
+    db: Path,
+    *,
+    path: str,
+    title: str,
+    text: str,
+    chunk_index: int = 0,
+    published: bool = True,
+) -> None:
+    with sqlite3.connect(db) as conn:
+        conn.execute(
+            """
+            INSERT OR IGNORE INTO documents(
+                path,
+                title,
+                author,
+                published
+            ) VALUES (?, ?, ?, ?)
+            """,
+            (
+                path,
+                title,
+                "Daniel Hladek",
+                1 if published else 0,
+            ),
+        )
+        conn.execute(
+            """
+            INSERT INTO chunks(
+                chunk_id,
+                document_path,
+                title,
+                author,
+                published,
+                chunk_index,
+                heading_paths_json,
+                text
+            ) VALUES (?, ?, ?, ?, ?, ?, ?, ?)
+            """,
+            (
+                f"{path}::chunk-{chunk_index}",
+                path,
+                title,
+                "Daniel Hladek",
+                1 if published else 0,
+                chunk_index,
+                "[]",
+                text,
+            ),
+        )
+
+
+def base_result(path: str, title: str) -> dict:
+    return {
+        "chunk_id": f"{path}::chunk-9",
+        "document_path": path,
+        "title": title,
+        "author": "Daniel Hladek",
+        "published": True,
+        "chunk_index": 9,
+        "heading_paths": [],
+        "text": "menej relevantný úsek",
+        "source_url": "https://example.invalid/base",
+    }
+
+
+def test_canonical_student_main_path_maps_child_document() -> None:
+    assert canonical_student_main_path(
+        "pages/students/2016/jakub_maruniak/dp2021/README.md"
+    ) == "pages/students/2016/jakub_maruniak/README.md"
+
+
+def test_exact_person_title_anchors_own_student_document(tmp_path: Path) -> None:
+    db = create_db(tmp_path)
+    path = "pages/students/2018/ondrej_megela/README.md"
+    add_document(
+        db,
+        path=path,
+        title="Ondrej Megela",
+        text=(
+            "Ondrej Megela. Neurónové siete a neurónové "
+            "jazykové modelovanie typu BERT."
+        ),
+    )
+    wrong_path = "pages/students/2016/patrik_pavlisin/README.md"
+    add_document(
+        db,
+        path=wrong_path,
+        title="Patrik Pavlišin",
+        text="Ondrej Megela je spomenutý pri neurónových sieťach.",
+    )
+
+    result = expand_results_with_supplemental_sources(
+        db,
+        "Ondrej Megela neurónové siete dokument študent",
+        [base_result(wrong_path, "Patrik Pavlišin")],
+        published_only=True,
+        limit=5,
+    )
+
+    assert result[0]["document_path"] == path
+    assert result[0]["title"] == "Ondrej Megela"
+
+
+def test_student_family_evidence_includes_child_document(tmp_path: Path) -> None:
+    db = create_db(tmp_path)
+    main = "pages/students/2016/jakub_maruniak/README.md"
+    child = "pages/students/2016/jakub_maruniak/dp2021/README.md"
+    add_document(
+        db,
+        path=main,
+        title="Jakub Maruniak",
+        text="Jakub Maruniak. Rok začiatku štúdia: 2016.",
+    )
+    add_document(
+        db,
+        path=child,
+        title="Diplomová práca Jakuba Maruniaka",
+        text=(
+            "Jakub Maruniak. Diplomová práca 2021. "
+            "Názov: Anotácia a rozpoznávanie pomenovaných entít "
+            "v slovenskom jazyku."
+        ),
+    )
+
+    result = expand_results_with_supplemental_sources(
+        db,
+        "Jakub Maruniak diplomová práca názov",
+        [base_result(main, "Jakub Maruniak")],
+        published_only=True,
+        limit=5,
+    )
+
+    blocks = result[0].get("family_evidence_blocks") or []
+    assert blocks
+    assert any(block["document_path"] == child for block in blocks)
+    assert any("Anotácia" in block["focus_text"] for block in blocks)
+
+
+def test_reverse_lookup_adds_document_with_exact_work_phrase(tmp_path: Path) -> None:
+    db = create_db(tmp_path)
+    expected = "pages/students/2016/patrik_pavlisin/README.md"
+    add_document(
+        db,
+        path=expected,
+        title="Patrik Pavlišin",
+        text=(
+            "Bakalárska práca 2020. "
+            "Názov bakalárskej práce: Metódy automatického prekladu."
+        ),
+    )
+    add_document(
+        db,
+        path="pages/students/2020/vladyslav_krupko/README.md",
+        title="Vladyslav Krupko",
+        text="Strojový preklad je súčasťou úloh.",
+    )
+
+    result = expand_results_with_supplemental_sources(
+        db,
+        "Metódy automatického prekladu študent dokument téma",
+        [],
+        published_only=True,
+        limit=5,
+    )
+
+    assert result[0]["document_path"] == expected
+
+
+def test_bilingual_reverse_lookup_finds_internship(tmp_path: Path) -> None:
+    db = create_db(tmp_path)
+    expected = "pages/interns/bogdan_paul_chis/README.md"
+    add_document(
+        db,
+        path=expected,
+        title="Bogdan Paul Chiș",
+        text=(
+            "Topic: (multilingual) Triplet extraction from medical data. "
+            "Goal: Construct a knowledge graph from medical package inserts."
+        ),
+    )
+    add_document(
+        db,
+        path="pages/topics/otvorene/README.md",
+        title="Otvorené projekty",
+        text="Multilingual extraction from medical documents is an open topic.",
+    )
+
+    result = expand_results_with_supplemental_sources(
+        db,
+        "multilinguálna extrakcia trojíc z medicínskych dát",
+        [],
+        published_only=True,
+        limit=5,
+    )
+
+    assert result[0]["document_path"] == expected
+
+
+def test_exact_topic_page_title_is_promoted(tmp_path: Path) -> None:
+    db = create_db(tmp_path)
+    topic = "pages/topics/translation/README.md"
+    add_document(
+        db,
+        path=topic,
+        title="Strojový preklad",
+        text="Štatistický strojový preklad. Neurónový strojový preklad.",
+    )
+    add_document(
+        db,
+        path="pages/students/2016/patrik_pavlisin/README.md",
+        title="Patrik Pavlišin",
+        text="Metódy automatického a strojového prekladu.",
+    )
+
+    result = expand_results_with_supplemental_sources(
+        db,
+        "Strojový preklad projektová stránka informačná stránka",
+        [],
+        published_only=True,
+        limit=5,
+    )
+
+    assert result[0]["document_path"] == topic
+
+
+def test_generic_question_prefers_root_topic_page(tmp_path: Path) -> None:
+    db = create_db(tmp_path)
+    root = "pages/topics/question/README.md"
+    child = "pages/topics/question/validacie/README.md"
+    add_document(
+        db,
+        path=root,
+        title="Question Answering",
+        text=(
+            "Anotácia otázok. Pre každý odsek má vzniknúť 5 otázok. "
+            "Používa sa anotačný nástroj Prodigy."
+        ),
+    )
+    add_document(
+        db,
+        path=child,
+        title="Validácia otázok a odpovedí",
+        text="Anotácia otázok a validácia odsekov.",
+    )
+
+    result = expand_results_with_supplemental_sources(
+        db,
+        "Koľko otázok má vzniknúť pre každý odsek pri anotácii otázok?",
+        [],
+        published_only=True,
+        limit=5,
+    )
+
+    assert result[0]["document_path"] == root
+
+
+def test_multi_document_query_adds_multiple_sources(tmp_path: Path) -> None:
+    db = create_db(tmp_path)
+    paths = [
+        "pages/students/2022/jan_ptak/README.md",
+        "pages/students/2022/jan_malinovsky/README.md",
+        "pages/students/2021/matej_scislak/README.md",
+    ]
+
+    for index, path in enumerate(paths):
+        add_document(
+            db,
+            path=path,
+            title=f"Student {index}",
+            text="RAG a GraphRAG, retrieval augmented generation.",
+        )
+
+    result = expand_results_with_supplemental_sources(
+        db,
+        "Nájdi viacero dokumentov, ktoré riešia RAG alebo GraphRAG.",
+        [],
+        published_only=True,
+        limit=10,
+    )
+
+    assert is_multi_document_query(
+        "Nájdi viacero dokumentov, ktoré riešia RAG alebo GraphRAG."
+    )
+    assert len(result) >= 2
+    assert len({item["document_path"] for item in result}) >= 2
+
+
+def test_unpublished_supplement_is_excluded(tmp_path: Path) -> None:
+    db = create_db(tmp_path)
+    add_document(
+        db,
+        path="pages/topics/secret/README.md",
+        title="Tajný projekt",
+        text="Tajný projekt a unikátny výraz xyzabc.",
+        published=False,
+    )
+
+    result = expand_results_with_supplemental_sources(
+        db,
+        "Tajný projekt xyzabc",
+        [],
+        published_only=True,
+        limit=5,
+    )
+
+    assert result == []
+
+
+def test_missing_database_is_safe_noop(tmp_path: Path) -> None:
+    base = [
+        base_result(
+            "pages/students/2016/jan_holp/README.md",
+            "Ján Holp",
+        )
+    ]
+
+    result = expand_results_with_supplemental_sources(
+        tmp_path / "missing.sqlite",
+        "Ján Holp",
+        base,
+        published_only=True,
+        limit=5,
+    )
+
+    assert result == base