feat(consume): fuse concept signals by RRF with declared tie-breaks

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tests/test_okf_consume.py

@@ -380,3 +380,61 @@ def test_document_scores_are_identical_across_two_calls() -> None:
     assert okf_consume.document_scores(FIXTURE, question) == okf_consume.document_scores(
         FIXTURE, question
     )
+
+
+# --- Step 6: stage-two concept ranking, fused by RRF --------------------------
+
+
+def _fixture_concepts() -> list[okf_consume.Concept]:
+    return [
+        okf_consume.read_concept(
+            FIXTURE / f"{concept_id}.md",
+            bundle_root=FIXTURE,
+            root_bundle_id="consume-fixture",
+        )
+        for concept_id in okf_consume.enumerate_concepts(FIXTURE)
+    ]
+
+
+def test_concepts_tying_on_every_signal_come_back_in_concept_id_order() -> None:
+    concepts = _fixture_concepts()
+    # A question matching nothing makes every signal identical, so the ONLY
+    # thing left deciding the order is the declared tie-break.
+    ranked = okf_consume.concept_scores(concepts, "zzzz qqqq", {})
+    ids = [concept.concept_id for concept, _ in ranked]
+    assert ids == sorted(ids)
+
+
+def test_reversing_the_input_order_does_not_change_the_output_order() -> None:
+    concepts = _fixture_concepts()
+    forward = [c.concept_id for c, _ in okf_consume.concept_scores(concepts, "zzzz qqqq", {})]
+    backward = [
+        c.concept_id
+        for c, _ in okf_consume.concept_scores(list(reversed(concepts)), "zzzz qqqq", {})
+    ]
+    assert forward == backward
+
+
+def test_a_concept_in_a_high_scoring_document_outranks_an_equally_lexical_one() -> None:
+    concepts = _fixture_concepts()
+    question = "Hvordan skal prisene fylles ut?"
+    lifted = okf_consume.concept_scores(concepts, question, {"krav": 10.0, "dyp": 0.0})
+    dropped = okf_consume.concept_scores(concepts, question, {"krav": 0.0, "dyp": 10.0})
+    krav_first = [c.concept_id for c, _ in lifted].index("krav/prissammenstilling")
+    krav_later = [c.concept_id for c, _ in dropped].index("krav/prissammenstilling")
+    assert krav_first < krav_later
+
+
+def test_the_ranked_order_is_identical_across_two_calls() -> None:
+    concepts = _fixture_concepts()
+    scores = okf_consume.document_scores(FIXTURE, "Hvordan skal prisene fylles ut?")
+    first = okf_consume.concept_scores(concepts, "Hvordan skal prisene fylles ut?", scores)
+    second = okf_consume.concept_scores(concepts, "Hvordan skal prisene fylles ut?", scores)
+    assert [c.concept_id for c, _ in first] == [c.concept_id for c, _ in second]
+
+
+def test_the_price_concept_leads_on_the_price_question_in_the_fixture() -> None:
+    concepts = _fixture_concepts()
+    scores = okf_consume.document_scores(FIXTURE, "Hvordan skal prisene fylles ut?")
+    ranked = okf_consume.concept_scores(concepts, "Hvordan skal prisene fylles ut?", scores)
+    assert ranked[0][0].concept_id == "krav/prissammenstilling"