session-memory Phase 0: Tier1/Tier2 store (T03)

- session_memory/core/store.py: SQLite rows + blob-dir bodies, idempotent
  ingest on (session_uid,seq), Tier1/Tier2 usage accounting, evict_raw that
  drops raw but preserves the digest; watermark columns authoritative
- tests/test_store.py: ingest idempotency, accounting, eviction invariant

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/test_store.py

@@ -0,0 +1,82 @@
+"""Store tests (T03): idempotent ingest, usage accounting, eviction."""
+
+import os
+import sys
+
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+from session_memory.adapters.claude import Normalized  # noqa: E402
+from session_memory.core.schema import Cost, Session, SessionEvent  # noqa: E402
+from session_memory.core.store import Store  # noqa: E402
+
+
+def _bundle(uid_native="s1", n_events=3):
+    s = Session(
+        session_uid=Session.make_uid("claude", uid_native),
+        flavor="claude", native_session_id=uid_native,
+        repo="agentic-resources", domain="helix_forge",
+        cost=Cost(input_tokens=10),
+    )
+    events, blobs = [], {}
+    for i in range(n_events):
+        ref = f"blob://{uid_native}/{i}"
+        events.append(SessionEvent(session_uid=s.session_uid, seq=i, kind="assistant_msg",
+                                   payload_ref=ref, summary=f"msg {i}"))
+        blobs[ref] = "x" * 100
+    return Normalized(session=s, events=events, blobs=blobs)
+
+
+def _store(tmp_path):
+    return Store(str(tmp_path / "mem.db"), str(tmp_path / "blobs"))
+
+
+def test_ingest_and_read_back(tmp_path):
+    st = _store(tmp_path)
+    b = _bundle("s1", 3)
+    st.ingest(b)
+    s = st.get_session(b.session.session_uid)
+    assert s is not None and s.ingested_at is not None
+    assert st.count_events(b.session.session_uid) == 3
+    assert st.tier1_usage_bytes() > 0
+
+
+def test_ingest_is_idempotent(tmp_path):
+    st = _store(tmp_path)
+    b = _bundle("s1", 3)
+    st.ingest(b)
+    before = st.tier1_usage_bytes()
+    st.ingest(b)  # re-run same sweep
+    assert st.count_events(b.session.session_uid) == 3  # no duplicate rows
+    assert st.tier1_usage_bytes() == before  # blobs upserted, not doubled
+
+
+def test_digest_sets_analyzed_and_tier2_bytes(tmp_path):
+    st = _store(tmp_path)
+    b = _bundle("s1", 2)
+    st.ingest(b)
+    assert st.get_session(b.session.session_uid).analyzed_at is None
+    st.write_digest(b.session.session_uid, {"outcome": "success", "tools": {"Edit": 1}})
+    assert st.get_session(b.session.session_uid).analyzed_at is not None
+    assert st.tier2_usage_bytes() > 0
+    assert st.get_digest(b.session.session_uid)["outcome"] == "success"
+
+
+def test_evict_raw_keeps_digest_drops_raw(tmp_path):
+    st = _store(tmp_path)
+    b = _bundle("s1", 3)
+    st.ingest(b)
+    st.write_digest(b.session.session_uid, {"outcome": "unknown"})
+    blob_dir_files_before = sum(len(f) for _, _, f in os.walk(str(tmp_path / "blobs")))
+    assert blob_dir_files_before > 0
+
+    freed = st.evict_raw(b.session.session_uid)
+    assert freed > 0
+    assert st.count_events(b.session.session_uid) == 0          # raw gone
+    assert st.get_events(b.session.session_uid) == []
+    assert st.get_session(b.session.session_uid).evicted_at is not None
+    assert st.get_digest(b.session.session_uid) is not None     # Tier 2 preserved
+    # blob files removed from disk
+    remaining = [f for _, _, fs in os.walk(str(tmp_path / "blobs")) for f in fs]
+    assert remaining == []
+    # evicted session no longer counts toward Tier 1 usage
+    assert st.tier1_usage_bytes() == 0