fix: OSS Python SDK hygiene batch, 9 small bug fixes (#6770)

tests/rerankers/conftest.py

@@ -1,3 +1,5 @@
+import sys
+from types import ModuleType
 from unittest.mock import MagicMock, patch
 
 import pytest
@@ -9,3 +11,33 @@ def mock_llm():
         mock_llm_instance = MagicMock()
         mock_factory.create.return_value = mock_llm_instance
         yield mock_factory, mock_llm_instance
+
+
+@pytest.fixture
+def mock_cohere(monkeypatch):
+    """Provide a fake ``cohere`` module so CohereReranker imports/constructs."""
+    fake_cohere = ModuleType("cohere")
+    fake_client = MagicMock()
+    fake_cohere.Client = MagicMock(return_value=fake_client)
+    monkeypatch.setitem(sys.modules, "cohere", fake_cohere)
+
+    import mem0.reranker.cohere_reranker as cohere_reranker
+
+    monkeypatch.setattr(cohere_reranker, "cohere", fake_cohere, raising=False)
+    monkeypatch.setattr(cohere_reranker, "COHERE_AVAILABLE", True, raising=False)
+    return cohere_reranker, fake_client
+
+
+@pytest.fixture
+def mock_zero_entropy(monkeypatch):
+    """Provide a fake ``zeroentropy`` module so ZeroEntropyReranker imports."""
+    fake_module = ModuleType("zeroentropy")
+    fake_client = MagicMock()
+    fake_module.ZeroEntropy = MagicMock(return_value=fake_client)
+    monkeypatch.setitem(sys.modules, "zeroentropy", fake_module)
+
+    import mem0.reranker.zero_entropy_reranker as zero_entropy_reranker
+
+    monkeypatch.setattr(zero_entropy_reranker, "ZeroEntropy", fake_module.ZeroEntropy, raising=False)
+    monkeypatch.setattr(zero_entropy_reranker, "ZERO_ENTROPY_AVAILABLE", True, raising=False)
+    return zero_entropy_reranker, fake_client

tests/rerankers/test_reranker_fallback_no_mutation.py

@@ -0,0 +1,75 @@
+"""Regression tests pinning that the reranker fallback path never mutates caller-owned documents."""
+
+from unittest.mock import MagicMock, patch
+
+from mem0.configs.rerankers.cohere import CohereRerankerConfig
+from mem0.configs.rerankers.huggingface import HuggingFaceRerankerConfig
+from mem0.configs.rerankers.sentence_transformer import (
+    SentenceTransformerRerankerConfig,
+)
+from mem0.configs.rerankers.zero_entropy import ZeroEntropyRerankerConfig
+from mem0.reranker.huggingface_reranker import HuggingFaceReranker
+from mem0.reranker.sentence_transformer_reranker import SentenceTransformerReranker
+
+
+def _docs(n):
+    return [{"memory": f"doc{i}"} for i in range(n)]
+
+
+class TestCohereFallbackNoMutation:
+    def test_fallback_does_not_mutate_original_documents(self, mock_cohere):
+        module, fake_client = mock_cohere
+        fake_client.rerank.side_effect = RuntimeError("API error")
+
+        reranker = module.CohereReranker(CohereRerankerConfig(api_key="test-key"))
+        documents = _docs(3)
+        result = reranker.rerank("query", documents)
+
+        assert all("rerank_score" not in doc for doc in documents)
+        assert all(doc["rerank_score"] == 0.0 for doc in result)
+
+
+class TestZeroEntropyFallbackNoMutation:
+    def test_fallback_does_not_mutate_original_documents(self, mock_zero_entropy):
+        module, fake_client = mock_zero_entropy
+        fake_client.models.rerank.side_effect = RuntimeError("API error")
+
+        reranker = module.ZeroEntropyReranker(ZeroEntropyRerankerConfig(api_key="test-key"))
+        documents = _docs(3)
+        result = reranker.rerank("query", documents)
+
+        assert all("rerank_score" not in doc for doc in documents)
+        assert all(doc["rerank_score"] == 0.0 for doc in result)
+
+
+class TestHuggingFaceFallbackNoMutation:
+    def test_fallback_does_not_mutate_original_documents(self):
+        with (
+            patch("mem0.reranker.huggingface_reranker.AutoTokenizer") as mock_tokenizer_cls,
+            patch("mem0.reranker.huggingface_reranker.AutoModelForSequenceClassification") as mock_model_cls,
+        ):
+            mock_tokenizer = MagicMock(side_effect=RuntimeError("tokenizer error"))
+            mock_tokenizer_cls.from_pretrained.return_value = mock_tokenizer
+            mock_model_cls.from_pretrained.return_value = MagicMock()
+
+            reranker = HuggingFaceReranker(HuggingFaceRerankerConfig())
+            documents = _docs(3)
+            result = reranker.rerank("query", documents)
+
+        assert all("rerank_score" not in doc for doc in documents)
+        assert all(doc["rerank_score"] == 0.0 for doc in result)
+
+
+class TestSentenceTransformerFallbackNoMutation:
+    def test_fallback_does_not_mutate_original_documents(self):
+        with patch("mem0.reranker.sentence_transformer_reranker.CrossEncoder") as mock_cross_encoder_cls:
+            mock_model = MagicMock()
+            mock_model.predict.side_effect = RuntimeError("predict error")
+            mock_cross_encoder_cls.return_value = mock_model
+
+            reranker = SentenceTransformerReranker(SentenceTransformerRerankerConfig())
+            documents = _docs(3)
+            result = reranker.rerank("query", documents)
+
+        assert all("rerank_score" not in doc for doc in documents)
+        assert all(doc["rerank_score"] == 0.0 for doc in result)

tests/rerankers/test_reranker_fallback_topk.py

@@ -1,52 +1,9 @@
-"""Regression tests for the reranker fallback path honoring ``config.top_k``.
-
-When the underlying rerank call fails, the reranker falls back to returning the
-documents in their original order. That fallback must still respect the
-configured ``top_k`` limit, exactly like the success path does. The HuggingFace
-and SentenceTransformer rerankers already behave this way; these tests pin the
-same contract for the Cohere and ZeroEntropy rerankers.
-"""
-
-import sys
-from types import ModuleType
-from unittest.mock import MagicMock
-
-import pytest
+"""Regression tests pinning that the reranker fallback path still honors ``config.top_k``."""
 
 from mem0.configs.rerankers.cohere import CohereRerankerConfig
 from mem0.configs.rerankers.zero_entropy import ZeroEntropyRerankerConfig
 
 
-@pytest.fixture
-def mock_cohere(monkeypatch):
-    """Provide a fake ``cohere`` module so CohereReranker imports/constructs."""
-    fake_cohere = ModuleType("cohere")
-    fake_client = MagicMock()
-    fake_cohere.Client = MagicMock(return_value=fake_client)
-    monkeypatch.setitem(sys.modules, "cohere", fake_cohere)
-
-    import mem0.reranker.cohere_reranker as cohere_reranker
-
-    monkeypatch.setattr(cohere_reranker, "cohere", fake_cohere, raising=False)
-    monkeypatch.setattr(cohere_reranker, "COHERE_AVAILABLE", True, raising=False)
-    return cohere_reranker, fake_client
-
-
-@pytest.fixture
-def mock_zero_entropy(monkeypatch):
-    """Provide a fake ``zeroentropy`` module so ZeroEntropyReranker imports."""
-    fake_module = ModuleType("zeroentropy")
-    fake_client = MagicMock()
-    fake_module.ZeroEntropy = MagicMock(return_value=fake_client)
-    monkeypatch.setitem(sys.modules, "zeroentropy", fake_module)
-
-    import mem0.reranker.zero_entropy_reranker as zero_entropy_reranker
-
-    monkeypatch.setattr(zero_entropy_reranker, "ZeroEntropy", fake_module.ZeroEntropy, raising=False)
-    monkeypatch.setattr(zero_entropy_reranker, "ZERO_ENTROPY_AVAILABLE", True, raising=False)
-    return zero_entropy_reranker, fake_client
-
-
 def _docs(n):
     return [{"memory": f"doc{i}"} for i in range(n)]