feat(web): Core Refactor Phase A — extract sampling and cache modules; add adaptive TTL + eviction heuristics, Redis PoC, and metrics wiring. Tests added for TTL, eviction, exports, splash-adaptive, card index, and service worker. Docs+roadmap updated.

code/tests/test_preview_export_endpoints.py

@@ -0,0 +1,58 @@
+from typing import Set
+
+from fastapi.testclient import TestClient
+
+from code.web.app import app  # FastAPI instance
+from code.web.services.theme_catalog_loader import load_index
+
+
+def _first_theme_slug() -> str:
+    idx = load_index()
+    # Deterministic ordering for test stability
+    return sorted(idx.slug_to_entry.keys())[0]
+
+
+def test_preview_export_json_and_csv_curated_only_round_trip():
+    slug = _first_theme_slug()
+    client = TestClient(app)
+
+    # JSON full sample
+    r = client.get(f"/themes/preview/{slug}/export.json", params={"curated_only": 0, "limit": 12})
+    assert r.status_code == 200, r.text
+    data = r.json()
+    assert data["ok"] is True
+    assert data["theme_id"] == slug
+    assert data["count"] == len(data["items"]) <= 12  # noqa: SIM300
+    required_keys_sampled = {"name", "roles", "score", "rarity", "mana_cost", "color_identity_list", "pip_colors"}
+    sampled_role_set = {"payoff", "enabler", "support", "wildcard"}
+    assert data["items"], "expected non-empty preview sample"
+    for item in data["items"]:
+        roles = set(item.get("roles") or [])
+        # Curated examples & synthetic placeholders don't currently carry full card DB fields
+        if roles.intersection(sampled_role_set):
+            assert required_keys_sampled.issubset(item.keys()), f"sampled card missing expected fields: {item}"
+        else:
+            assert {"name", "roles", "score"}.issubset(item.keys())
+
+    # JSON curated_only variant: ensure only curated/synthetic roles remain
+    r2 = client.get(f"/themes/preview/{slug}/export.json", params={"curated_only": 1, "limit": 12})
+    assert r2.status_code == 200, r2.text
+    curated = r2.json()
+    curated_roles_allowed: Set[str] = {"example", "curated_synergy", "synthetic"}
+    for item in curated["items"]:
+        roles = set(item.get("roles") or [])
+        assert roles, "item missing roles"
+        assert roles.issubset(curated_roles_allowed), f"unexpected sampled role present: {roles}"
+
+    # CSV export header stability + curated_only path
+    r3 = client.get(f"/themes/preview/{slug}/export.csv", params={"curated_only": 1, "limit": 12})
+    assert r3.status_code == 200, r3.text
+    text = r3.text.splitlines()
+    assert text, "empty CSV response"
+    header = text[0].strip()
+    assert header == "name,roles,score,rarity,mana_cost,color_identity_list,pip_colors,reasons,tags"
+    # Basic sanity: curated_only CSV should not contain a sampled role token
+    sampled_role_tokens = {"payoff", "enabler", "support", "wildcard"}
+    body = "\n".join(text[1:])
+    for tok in sampled_role_tokens:
+        assert f";{tok}" not in body, f"sampled role {tok} leaked into curated_only CSV"