mnemosyne/tests/test_pgvector_backend.py

"""Tests for the PostgreSQL + pgvector backend.

Unit tests use mocked asyncpg connections to verify SQL generation and
data conversion without requiring a database. Integration tests require
a running PostgreSQL instance (Docker on port 5433) and are skipped
automatically when unavailable.
"""

from __future__ import annotations

import asyncio
import json
import os
import socket
import uuid
from datetime import datetime, timezone
from typing import Any
from unittest.mock import AsyncMock, MagicMock, patch

import numpy as np
import pytest

from mnemosyne.object_store import StoredObject, _estimate_tokens
from mnemosyne.pgvector_backend import (
    PgVectorBackend,
    _parse_jsonb,
    _parse_timestamp,
    _row_to_stored_object,
)


class _MockPool:
    """A mock asyncpg pool that properly supports async context manager on acquire()."""

    def __init__(self, conn: AsyncMock):
        self._conn = conn

    def acquire(self):
        return _MockAcquire(self._conn)


class _MockAcquire:
    """Async context manager returned by pool.acquire()."""

    def __init__(self, conn: AsyncMock):
        self._conn = conn

    async def __aenter__(self):
        return self._conn

    async def __aexit__(self, *args):
        return False


def _make_mock_pool(conn: AsyncMock) -> _MockPool:
    """Create a mock pool with proper async context manager support."""
    return _MockPool(conn)


# ── Helpers ──────────────────────────────────────────────────


def _make_stored_object(
    session_id: str = "test-session",
    content: str = "Test content for pgvector backend",
    *,
    object_type: str = "file_context",
    source_tool: str | None = "Read",
    source_key: str | None = None,
    stub: str | None = None,
    embedding: list[float] | None = None,
    object_id: str | None = None,
) -> StoredObject:
    """Create a StoredObject with sensible defaults for testing."""
    oid = object_id or uuid.uuid4().hex
    return StoredObject(
        id=oid,
        session_id=session_id,
        object_type=object_type,
        source_tool=source_tool,
        source_key=source_key,
        content_full=content,
        summary_detailed=None,
        summary_compact=None,
        stub=stub or f"{object_type}: test object",
        tokens_l0=_estimate_tokens(content),
        tokens_l3=_estimate_tokens(stub or f"{object_type}: test object"),
        embedding=embedding or [0.1] * 384,
        created_at="2025-01-01T00:00:00+00:00",
        last_accessed="2025-01-01T00:00:00+00:00",
    )


def _make_mock_row(
    obj: StoredObject | None = None,
    *,
    session_external_id: str = "test-session",
    similarity: float | None = None,
) -> MagicMock:
    """Create a mock asyncpg.Record from a StoredObject."""
    if obj is None:
        obj = _make_stored_object()

    row = MagicMock()
    row_data: dict[str, Any] = {
        "id": uuid.UUID(obj.id) if len(obj.id) == 32 else uuid.uuid4(),
        "session_id": uuid.uuid4(),
        "session_external_id": session_external_id,
        "object_type": obj.object_type,
        "source_tool": obj.source_tool,
        "source_key": obj.source_key,
        "content_full": obj.content_full,
        "summary_detailed": obj.summary_detailed,
        "summary_compact": obj.summary_compact,
        "stub": obj.stub,
        "losses_l1": obj.losses_l1,
        "losses_l2": obj.losses_l2,
        "can_answer_l1": obj.can_answer_l1,
        "can_answer_l2": obj.can_answer_l2,
        "fault_when": obj.fault_when,
        "key_entities": obj.key_entities,
        "tags": obj.tags,
        "current_fidelity": obj.current_fidelity,
        "pinned": obj.pinned,
        "tokens_l0": obj.tokens_l0,
        "tokens_l1": obj.tokens_l1,
        "tokens_l2": obj.tokens_l2,
        "tokens_l3": obj.tokens_l3,
        "source_turn_start": obj.source_turn_start,
        "source_turn_end": obj.source_turn_end,
        "embedding": np.array(obj.embedding, dtype=np.float32) if obj.embedding else None,
        "created_at": datetime(2025, 1, 1, tzinfo=timezone.utc),
        "last_accessed": datetime(2025, 1, 1, tzinfo=timezone.utc),
        "access_count": obj.access_count,
        "fault_count": obj.fault_count,
        "micro_fault_count": obj.micro_fault_count,
    }
    if similarity is not None:
        row_data["similarity"] = similarity

    row.__getitem__ = lambda self, key: row_data[key]
    return row


def _pg_available() -> bool:
    """Check if PostgreSQL is reachable on port 5433."""
    try:
        with socket.create_connection(("localhost", 5433), timeout=1):
            return True
    except (OSError, ConnectionRefusedError):
        return False


# ── Unit Tests: Data Conversion ──────────────────────────────


class TestParseJsonb:
    def test_none_returns_empty_list(self):
        assert _parse_jsonb(None) == []

    def test_list_passthrough(self):
        assert _parse_jsonb(["a", "b", "c"]) == ["a", "b", "c"]

    def test_list_converts_to_strings(self):
        assert _parse_jsonb([1, 2, 3]) == ["1", "2", "3"]

    def test_json_string(self):
        assert _parse_jsonb('["x", "y"]') == ["x", "y"]

    def test_invalid_json_string(self):
        assert _parse_jsonb("not json") == []

    def test_empty_list(self):
        assert _parse_jsonb([]) == []


class TestParseTimestamp:
    def test_iso_format(self):
        dt = _parse_timestamp("2025-01-01T00:00:00+00:00")
        assert dt.year == 2025
        assert dt.tzinfo is not None

    def test_empty_string_returns_now(self):
        dt = _parse_timestamp("")
        assert dt.tzinfo is not None
        # Should be close to now
        diff = abs((datetime.now(timezone.utc) - dt).total_seconds())
        assert diff < 5

    def test_naive_timestamp_gets_utc(self):
        dt = _parse_timestamp("2025-06-15T12:00:00")
        assert dt.tzinfo == timezone.utc

    def test_invalid_returns_now(self):
        dt = _parse_timestamp("not-a-date")
        assert dt.tzinfo is not None


class TestRowToStoredObject:
    def test_basic_conversion(self):
        obj = _make_stored_object()
        row = _make_mock_row(obj)
        result = _row_to_stored_object(row)

        assert result.object_type == "file_context"
        assert result.content_full == obj.content_full
        assert result.stub == obj.stub
        assert result.session_id == "test-session"
        assert result.current_fidelity == 0
        assert result.pinned is False

    def test_embedding_conversion(self):
        obj = _make_stored_object(embedding=[0.5] * 384)
        row = _make_mock_row(obj)
        result = _row_to_stored_object(row)

        assert len(result.embedding) == 384
        assert abs(result.embedding[0] - 0.5) < 1e-6

    def test_jsonb_fields_parsed(self):
        obj = _make_stored_object()
        obj.losses_l1 = ["detail_a", "detail_b"]
        obj.key_entities = ["src/main.py", "Config"]
        row = _make_mock_row(obj)
        result = _row_to_stored_object(row)

        assert result.losses_l1 == ["detail_a", "detail_b"]
        assert result.key_entities == ["src/main.py", "Config"]

    def test_tags_conversion(self):
        obj = _make_stored_object()
        obj.tags = ["auth", "middleware"]
        row = _make_mock_row(obj)
        result = _row_to_stored_object(row)

        assert result.tags == ["auth", "middleware"]

    def test_null_embedding(self):
        obj = _make_stored_object(embedding=[])
        row_data: dict[str, Any] = {
            "id": uuid.uuid4(),
            "session_id": uuid.uuid4(),
            "session_external_id": "test-session",
            "object_type": obj.object_type,
            "source_tool": obj.source_tool,
            "source_key": obj.source_key,
            "content_full": obj.content_full,
            "summary_detailed": obj.summary_detailed,
            "summary_compact": obj.summary_compact,
            "stub": obj.stub,
            "losses_l1": [],
            "losses_l2": [],
            "can_answer_l1": [],
            "can_answer_l2": [],
            "fault_when": [],
            "key_entities": [],
            "tags": [],
            "current_fidelity": 0,
            "pinned": False,
            "tokens_l0": obj.tokens_l0,
            "tokens_l1": None,
            "tokens_l2": None,
            "tokens_l3": obj.tokens_l3,
            "source_turn_start": None,
            "source_turn_end": None,
            "embedding": None,
            "created_at": datetime(2025, 1, 1, tzinfo=timezone.utc),
            "last_accessed": datetime(2025, 1, 1, tzinfo=timezone.utc),
            "access_count": 0,
            "fault_count": 0,
            "micro_fault_count": 0,
        }
        row = MagicMock()
        row.__getitem__ = lambda self, key: row_data[key]
        result = _row_to_stored_object(row)
        assert result.embedding == []


# ── Unit Tests: Backend Methods (Mocked DB) ─────────────────


class TestPgVectorBackendInit:
    def test_default_config(self):
        backend = PgVectorBackend()
        assert backend._host == "localhost"
        assert backend._port == 5433
        assert backend._database == "mnemosyne"
        assert backend._pool is None

    def test_custom_config(self):
        backend = PgVectorBackend(
            host="db.example.com",
            port=5432,
            database="mydb",
            user="myuser",
            password="secret",
            min_connections=5,
            max_connections=20,
        )
        assert backend._host == "db.example.com"
        assert backend._port == 5432
        assert backend._min_connections == 5
        assert backend._max_connections == 20

    def test_get_pool_raises_when_not_connected(self):
        backend = PgVectorBackend()
        with pytest.raises(RuntimeError, match="not connected"):
            backend._get_pool()


class TestPgVectorBackendStore:
    """Test store() with mocked pool."""

    async def test_store_calls_execute(self):
        backend = PgVectorBackend()
        mock_conn = AsyncMock()
        mock_conn.execute = AsyncMock()
        mock_conn.fetchrow = AsyncMock(return_value={"id": uuid.uuid4()})
        backend._pool = _make_mock_pool(mock_conn)

        obj = _make_stored_object(object_id=uuid.uuid4().hex)
        await backend.store(obj)

        # Should have called execute for the INSERT (store) and fetchrow for session upsert
        assert mock_conn.execute.called or mock_conn.fetchrow.called

    async def test_store_creates_session_if_needed(self):
        backend = PgVectorBackend()
        session_uuid = uuid.uuid4()

        mock_conn = AsyncMock()
        mock_conn.fetchrow = AsyncMock(return_value={"id": session_uuid})
        mock_conn.execute = AsyncMock()
        backend._pool = _make_mock_pool(mock_conn)

        obj = _make_stored_object(object_id=uuid.uuid4().hex)
        await backend.store(obj)

        # Session should be cached after creation
        assert "test-session" in backend._session_cache


class TestPgVectorBackendGet:
    """Test get() with mocked pool."""

    async def test_get_returns_none_when_not_found(self):
        backend = PgVectorBackend()
        mock_conn = AsyncMock()
        mock_conn.fetchrow = AsyncMock(return_value=None)
        backend._pool = _make_mock_pool(mock_conn)

        result = await backend.get(uuid.uuid4().hex)
        assert result is None

    async def test_get_returns_stored_object(self):
        backend = PgVectorBackend()
        obj = _make_stored_object(object_id=uuid.uuid4().hex)
        mock_row = _make_mock_row(obj)

        mock_conn = AsyncMock()
        mock_conn.fetchrow = AsyncMock(return_value=mock_row)
        backend._pool = _make_mock_pool(mock_conn)

        result = await backend.get(obj.id)
        assert result is not None
        assert result.content_full == obj.content_full


class TestPgVectorBackendGetBySession:
    """Test get_by_session() with mocked pool."""

    async def test_returns_empty_for_unknown_session(self):
        backend = PgVectorBackend()
        mock_conn = AsyncMock()
        mock_conn.fetchrow = AsyncMock(return_value=None)
        backend._pool = _make_mock_pool(mock_conn)

        result = await backend.get_by_session("nonexistent")
        assert result == []


class TestPgVectorBackendUpdateFidelity:
    """Test update_fidelity() with mocked pool."""

    async def test_update_fidelity_basic(self):
        backend = PgVectorBackend()
        mock_conn = AsyncMock()
        mock_conn.execute = AsyncMock()
        backend._pool = _make_mock_pool(mock_conn)

        await backend.update_fidelity(uuid.uuid4().hex, 1)
        assert mock_conn.execute.called

    async def test_update_fidelity_with_summary_l1(self):
        backend = PgVectorBackend()
        mock_conn = AsyncMock()
        mock_conn.execute = AsyncMock()
        backend._pool = _make_mock_pool(mock_conn)

        await backend.update_fidelity(
            uuid.uuid4().hex, 1, summary="A summary", losses=["lost detail"]
        )
        # Verify the SQL includes summary_detailed and losses_l1
        call_args = mock_conn.execute.call_args
        query = call_args[0][0]
        assert "summary_detailed" in query
        assert "losses_l1" in query

    async def test_update_fidelity_with_summary_l2(self):
        backend = PgVectorBackend()
        mock_conn = AsyncMock()
        mock_conn.execute = AsyncMock()
        backend._pool = _make_mock_pool(mock_conn)

        await backend.update_fidelity(uuid.uuid4().hex, 2, summary="Compact", losses=["more lost"])
        call_args = mock_conn.execute.call_args
        query = call_args[0][0]
        assert "summary_compact" in query
        assert "losses_l2" in query


class TestPgVectorBackendSearchByEmbedding:
    """Test search_by_embedding() with mocked pool."""

    async def test_returns_empty_for_unknown_session(self):
        backend = PgVectorBackend()
        mock_conn = AsyncMock()
        mock_conn.fetchrow = AsyncMock(return_value=None)
        backend._pool = _make_mock_pool(mock_conn)

        result = await backend.search_by_embedding("nonexistent", [0.1] * 384)
        assert result == []


class TestPgVectorBackendSearchByText:
    """Test search_by_text() with mocked pool."""

    async def test_returns_empty_for_unknown_session(self):
        backend = PgVectorBackend()
        mock_conn = AsyncMock()
        mock_conn.fetchrow = AsyncMock(return_value=None)
        backend._pool = _make_mock_pool(mock_conn)

        result = await backend.search_by_text("nonexistent", "test query")
        assert result == []


class TestPgVectorBackendDeleteSession:
    """Test delete_session() with mocked pool."""

    async def test_returns_zero_for_unknown_session(self):
        backend = PgVectorBackend()
        mock_conn = AsyncMock()
        mock_conn.fetchrow = AsyncMock(return_value=None)
        backend._pool = _make_mock_pool(mock_conn)

        result = await backend.delete_session("nonexistent")
        assert result == 0


class TestPgVectorBackendGetBySourceKey:
    """Test get_by_source_key() with mocked pool."""

    async def test_returns_none_for_unknown_session(self):
        backend = PgVectorBackend()
        mock_conn = AsyncMock()
        mock_conn.fetchrow = AsyncMock(return_value=None)
        backend._pool = _make_mock_pool(mock_conn)

        result = await backend.get_by_source_key("nonexistent", "src/main.py")
        assert result is None


class TestPgVectorBackendHealthCheck:
    """Test health_check()."""

    async def test_returns_false_when_not_connected(self):
        backend = PgVectorBackend()
        assert await backend.health_check() is False

    async def test_returns_true_with_healthy_pool(self):
        backend = PgVectorBackend()
        mock_conn = AsyncMock()
        mock_conn.fetchval = AsyncMock(return_value=1)
        backend._pool = _make_mock_pool(mock_conn)

        assert await backend.health_check() is True

    async def test_returns_false_on_error(self):
        backend = PgVectorBackend()
        mock_conn = AsyncMock()
        mock_conn.fetchval = AsyncMock(side_effect=Exception("connection lost"))
        backend._pool = _make_mock_pool(mock_conn)

        assert await backend.health_check() is False


class TestPgVectorBackendSessionCache:
    """Test session ID caching behavior."""

    async def test_session_cache_populated_on_ensure(self):
        backend = PgVectorBackend()
        session_uuid = uuid.uuid4()

        mock_conn = AsyncMock()
        mock_conn.fetchrow = AsyncMock(return_value={"id": session_uuid})
        backend._pool = _make_mock_pool(mock_conn)

        result = await backend.ensure_session("my-session", "claude-opus-4")
        assert result == session_uuid
        assert backend._session_cache["my-session"] == session_uuid

    async def test_session_cache_avoids_db_lookup(self):
        backend = PgVectorBackend()
        session_uuid = uuid.uuid4()
        backend._session_cache["cached-session"] = session_uuid

        # Pool shouldn't be needed since cache is populated
        backend._pool = _make_mock_pool(AsyncMock())

        result = await backend._resolve_session_id("cached-session")
        assert result == session_uuid

    async def test_close_clears_cache(self):
        backend = PgVectorBackend()
        backend._session_cache["test"] = uuid.uuid4()

        mock_pool = AsyncMock()
        mock_pool.close = AsyncMock()
        backend._pool = mock_pool

        await backend.close()
        assert len(backend._session_cache) == 0
        assert backend._pool is None


# ── Integration Tests (require Docker PostgreSQL) ────────────


_skip_no_pg = pytest.mark.skipif(
    not _pg_available(),
    reason="PostgreSQL not available on localhost:5433 (run: docker compose up -d)",
)


@_skip_no_pg
class TestPgVectorBackendIntegration:
    """Integration tests against a real PostgreSQL instance.

    These tests require Docker PostgreSQL running on port 5433 with
    the schema from sql/init.sql applied. Start with:
        cd ~/Projects/contextmanager && docker compose up -d
    """

    @pytest.fixture
    async def backend(self):
        """Create a connected backend and clean up after test."""
        b = PgVectorBackend(
            host="localhost",
            port=5433,
            database="mnemosyne",
            user="mnemosyne",
            password="mnemosyne_dev",
            min_connections=1,
            max_connections=3,
        )
        await b.connect()

        # Create a unique session for this test
        test_session = f"integration-test-{uuid.uuid4().hex[:8]}"
        yield b, test_session

        # Cleanup: delete test session data
        try:
            session_uuid = await b._resolve_session_id(test_session)
            if session_uuid is not None:
                pool = b._get_pool()
                async with pool.acquire() as conn:
                    await conn.execute(
                        "DELETE FROM semantic_objects WHERE session_id = $1",
                        session_uuid,
                    )
                    await conn.execute(
                        "DELETE FROM sessions WHERE id = $1",
                        session_uuid,
                    )
        except Exception:
            pass
        await b.close()

    async def test_health_check(self, backend):
        b, _ = backend
        assert await b.health_check() is True

    async def test_ensure_session(self, backend):
        b, test_session = backend
        session_uuid = await b.ensure_session(test_session, "claude-opus-4")
        assert isinstance(session_uuid, uuid.UUID)

        # Second call should return same UUID
        session_uuid2 = await b.ensure_session(test_session, "claude-opus-4")
        assert session_uuid == session_uuid2

    async def test_store_and_get(self, backend):
        b, test_session = backend
        await b.ensure_session(test_session)

        obj_id = uuid.uuid4().hex
        obj = _make_stored_object(
            session_id=test_session,
            content="Integration test content",
            object_id=obj_id,
        )
        await b.store(obj)

        retrieved = await b.get(obj_id)
        assert retrieved is not None
        assert retrieved.content_full == "Integration test content"
        assert retrieved.session_id == test_session
        assert retrieved.object_type == "file_context"

    async def test_store_upsert(self, backend):
        b, test_session = backend
        await b.ensure_session(test_session)

        obj_id = uuid.uuid4().hex
        obj = _make_stored_object(
            session_id=test_session,
            content="Original content",
            object_id=obj_id,
        )
        await b.store(obj)

        # Update the same object
        obj.content_full = "Updated content"
        await b.store(obj)

        retrieved = await b.get(obj_id)
        assert retrieved is not None
        assert retrieved.content_full == "Updated content"

    async def test_get_by_session(self, backend):
        b, test_session = backend
        await b.ensure_session(test_session)

        # Store 3 objects
        for i in range(3):
            obj = _make_stored_object(
                session_id=test_session,
                content=f"Content {i}",
                object_id=uuid.uuid4().hex,
            )
            await b.store(obj)

        results = await b.get_by_session(test_session)
        assert len(results) == 3

    async def test_get_by_session_fidelity_filter(self, backend):
        b, test_session = backend
        await b.ensure_session(test_session)

        # Store object at fidelity 0
        obj0 = _make_stored_object(
            session_id=test_session,
            content="Fidelity 0",
            object_id=uuid.uuid4().hex,
        )
        await b.store(obj0)

        # Store object at fidelity 4 (evicted)
        obj4 = _make_stored_object(
            session_id=test_session,
            content="Fidelity 4",
            object_id=uuid.uuid4().hex,
        )
        obj4.current_fidelity = 4
        await b.store(obj4)

        # Default: include all
        all_results = await b.get_by_session(test_session, fidelity_max=4)
        assert len(all_results) == 2

        # Exclude evicted
        active_results = await b.get_by_session(test_session, fidelity_max=3)
        assert len(active_results) == 1
        assert active_results[0].content_full == "Fidelity 0"

    async def test_update_fidelity(self, backend):
        b, test_session = backend
        await b.ensure_session(test_session)

        obj_id = uuid.uuid4().hex
        obj = _make_stored_object(
            session_id=test_session,
            content="Will be degraded",
            object_id=obj_id,
        )
        await b.store(obj)

        await b.update_fidelity(
            obj_id,
            1,
            summary="Detailed summary",
            losses=["lost some detail"],
        )

        retrieved = await b.get(obj_id)
        assert retrieved is not None
        assert retrieved.current_fidelity == 1
        assert retrieved.summary_detailed == "Detailed summary"

    async def test_search_by_embedding(self, backend):
        b, test_session = backend
        await b.ensure_session(test_session)

        # Store objects with different embeddings
        rng = np.random.default_rng(42)
        for i in range(5):
            vec = rng.standard_normal(384).astype(np.float32)
            vec = vec / np.linalg.norm(vec)
            obj = _make_stored_object(
                session_id=test_session,
                content=f"Embedding test {i}",
                object_id=uuid.uuid4().hex,
                embedding=vec.tolist(),
            )
            await b.store(obj)

        # Search with the first object's embedding
        query_vec = rng.standard_normal(384).astype(np.float32)
        query_vec = query_vec / np.linalg.norm(query_vec)

        results = await b.search_by_embedding(test_session, query_vec.tolist(), limit=3)
        assert len(results) <= 3
        # Results should be (StoredObject, float) tuples
        for obj, score in results:
            assert isinstance(obj, StoredObject)
            assert isinstance(score, float)
            assert -1.0 <= score <= 1.0

        # Scores should be in descending order
        scores = [s for _, s in results]
        assert scores == sorted(scores, reverse=True)

    async def test_search_by_text(self, backend):
        b, test_session = backend
        await b.ensure_session(test_session)

        obj = _make_stored_object(
            session_id=test_session,
            content="The authentication middleware validates JWT tokens and checks expiration dates",
            object_id=uuid.uuid4().hex,
        )
        await b.store(obj)

        obj2 = _make_stored_object(
            session_id=test_session,
            content="Database connection pooling configuration for PostgreSQL",
            object_id=uuid.uuid4().hex,
        )
        await b.store(obj2)

        # Search for auth-related content
        results = await b.search_by_text(test_session, "authentication JWT tokens")
        assert len(results) >= 1
        assert any("authentication" in r.content_full for r in results)

    async def test_delete_session(self, backend):
        b, test_session = backend
        await b.ensure_session(test_session)

        # Store some objects
        for i in range(3):
            obj = _make_stored_object(
                session_id=test_session,
                content=f"Delete test {i}",
                object_id=uuid.uuid4().hex,
            )
            await b.store(obj)

        count = await b.delete_session(test_session)
        assert count == 3

        # Verify they're gone
        results = await b.get_by_session(test_session)
        assert len(results) == 0

    async def test_get_by_source_key(self, backend):
        b, test_session = backend
        await b.ensure_session(test_session)

        obj = _make_stored_object(
            session_id=test_session,
            content="File content",
            source_key="src/main.py",
            object_id=uuid.uuid4().hex,
        )
        await b.store(obj)

        result = await b.get_by_source_key(test_session, "src/main.py")
        assert result is not None
        assert result.source_key == "src/main.py"

        # Non-existent key
        result2 = await b.get_by_source_key(test_session, "nonexistent.py")
        assert result2 is None

    async def test_get_by_source_key_returns_most_recent(self, backend):
        b, test_session = backend
        await b.ensure_session(test_session)

        # Store two objects with same source_key
        obj1 = _make_stored_object(
            session_id=test_session,
            content="Old version",
            source_key="src/config.py",
            object_id=uuid.uuid4().hex,
        )
        obj1.created_at = "2025-01-01T00:00:00+00:00"
        await b.store(obj1)

        obj2 = _make_stored_object(
            session_id=test_session,
            content="New version",
            source_key="src/config.py",
            object_id=uuid.uuid4().hex,
        )
        obj2.created_at = "2025-06-01T00:00:00+00:00"
        await b.store(obj2)

        result = await b.get_by_source_key(test_session, "src/config.py")
        assert result is not None
        assert result.content_full == "New version"

    async def test_session_isolation(self, backend):
        b, test_session = backend
        other_session = f"other-{uuid.uuid4().hex[:8]}"

        await b.ensure_session(test_session)
        await b.ensure_session(other_session)

        # Store in test_session
        obj = _make_stored_object(
            session_id=test_session,
            content="Session A content",
            object_id=uuid.uuid4().hex,
        )
        await b.store(obj)

        # Store in other_session
        obj2 = _make_stored_object(
            session_id=other_session,
            content="Session B content",
            object_id=uuid.uuid4().hex,
        )
        await b.store(obj2)

        # Each session should only see its own objects
        results_a = await b.get_by_session(test_session)
        results_b = await b.get_by_session(other_session)

        assert len(results_a) == 1
        assert results_a[0].content_full == "Session A content"
        assert len(results_b) == 1
        assert results_b[0].content_full == "Session B content"

        # Cleanup other session
        try:
            session_uuid = await b._resolve_session_id(other_session)
            if session_uuid:
                pool = b._get_pool()
                async with pool.acquire() as conn:
                    await conn.execute(
                        "DELETE FROM semantic_objects WHERE session_id = $1",
                        session_uuid,
                    )
                    await conn.execute(
                        "DELETE FROM sessions WHERE id = $1",
                        session_uuid,
                    )
        except Exception:
            pass