Apply Ruff formatting to rebased stack

headroom/proxy/savings_tracker.py

@@ -49,12 +49,7 @@ def _utc_now() -> datetime:
 
 
 def _to_utc_iso(dt: datetime) -> str:
-    return (
-        dt.astimezone(timezone.utc)
-        .replace(microsecond=0)
-        .isoformat()
-        .replace("+00:00", "Z")
-    )
+    return dt.astimezone(timezone.utc).replace(microsecond=0).isoformat().replace("+00:00", "Z")
 
 
 def _parse_timestamp(value: Any) -> datetime | None:
@@ -293,9 +288,7 @@ class SavingsTracker:
         path: str | None = None,
         max_history_points: int = DEFAULT_MAX_HISTORY_POINTS,
         max_history_age_days: int = DEFAULT_MAX_HISTORY_AGE_DAYS,
-        display_session_inactivity_minutes: int = (
-            DEFAULT_DISPLAY_SESSION_INACTIVITY_MINUTES
-        ),
+        display_session_inactivity_minutes: int = (DEFAULT_DISPLAY_SESSION_INACTIVITY_MINUTES),
     ) -> None:
         self._path = Path(path or get_default_savings_storage_path())
         self._max_history_points = max_history_points
@@ -472,9 +465,7 @@ class SavingsTracker:
             )
             total_before = session["tokens_saved"] + session["total_input_tokens"]
             session["savings_percent"] = round(
-                (session["tokens_saved"] / total_before * 100)
-                if total_before > 0
-                else 0.0,
+                (session["tokens_saved"] / total_before * 100) if total_before > 0 else 0.0,
                 2,
             )
             session["last_activity_at"] = _to_utc_iso(timestamp_dt)
@@ -584,9 +575,7 @@ class SavingsTracker:
                 "lifetime": dict(self._state["lifetime"]),
                 "display_session": self._display_session_snapshot_locked(),
                 "display_session_policy": {
-                    "rollover_inactivity_minutes": (
-                        self._display_session_inactivity_minutes
-                    ),
+                    "rollover_inactivity_minutes": (self._display_session_inactivity_minutes),
                 },
                 "history": history,
                 "retention": {
@@ -645,13 +634,9 @@ class SavingsTracker:
         if isinstance(lifetime_raw, dict):
             lifetime_requests = _coerce_int(lifetime_raw.get("requests"))
             lifetime_tokens_saved = _coerce_int(lifetime_raw.get("tokens_saved"))
-            lifetime_savings_usd = _coerce_float(
-                lifetime_raw.get("compression_savings_usd")
-            )
+            lifetime_savings_usd = _coerce_float(lifetime_raw.get("compression_savings_usd"))
             lifetime_input_tokens = _coerce_int(lifetime_raw.get("total_input_tokens"))
-            lifetime_input_cost_usd = _coerce_float(
-                lifetime_raw.get("total_input_cost_usd")
-            )
+            lifetime_input_cost_usd = _coerce_float(lifetime_raw.get("total_input_cost_usd"))
 
         if normalized_history:
             last = normalized_history[-1]
@@ -686,9 +671,7 @@ class SavingsTracker:
         }
 
         if normalized_history:
-            reference_time = (
-                _parse_timestamp(normalized_history[-1]["timestamp"]) or _utc_now()
-            )
+            reference_time = _parse_timestamp(normalized_history[-1]["timestamp"]) or _utc_now()
             original_state = self._state if hasattr(self, "_state") else None
             self._state = state
             try:
@@ -706,9 +689,7 @@ class SavingsTracker:
             return
 
         if self._max_history_age_days > 0:
-            cutoff = (reference_time or _utc_now()) - timedelta(
-                days=self._max_history_age_days
-            )
+            cutoff = (reference_time or _utc_now()) - timedelta(days=self._max_history_age_days)
             filtered = [
                 item
                 for item in history

tests/test_proxy_savings_history.py

@@ -43,9 +43,7 @@ def _record_request(
 def test_savings_tracker_helpers_normalize_inputs_and_paths(tmp_path, monkeypatch):
     override_path = tmp_path / "custom-savings.json"
     monkeypatch.setenv(HEADROOM_SAVINGS_PATH_ENV_VAR, str(override_path))
-    assert savings_tracker_module.get_default_savings_storage_path() == str(
-        override_path
-    )
+    assert savings_tracker_module.get_default_savings_storage_path() == str(override_path)
 
     monkeypatch.delenv(HEADROOM_SAVINGS_PATH_ENV_VAR, raising=False)
     default_path = savings_tracker_module.get_default_savings_storage_path()
@@ -119,10 +117,7 @@ def test_savings_tracker_sanitizes_legacy_state_and_applies_retention(tmp_path):
         "total_input_tokens": 0,
         "total_input_cost_usd": 0.0,
     }
-    assert (
-        snapshot["display_session"]
-        == savings_tracker_module._empty_display_session()
-    )
+    assert snapshot["display_session"] == savings_tracker_module._empty_display_session()
     assert snapshot["history"] == [
         {
             "timestamp": "2026-03-27T09:00:00Z",
@@ -152,10 +147,7 @@ def test_non_dict_savings_state_resets_to_default(tmp_path):
         "total_input_tokens": 0,
         "total_input_cost_usd": 0.0,
     }
-    assert (
-        snapshot["display_session"]
-        == savings_tracker_module._empty_display_session()
-    )
+    assert snapshot["display_session"] == savings_tracker_module._empty_display_session()
     assert snapshot["history"] == []
 
 
@@ -254,9 +246,7 @@ def test_litellm_resolution_and_savings_estimation_fallbacks(monkeypatch):
     ) == pytest.approx(0.2)
 
     fake_litellm.model_cost = {}
-    assert (
-        savings_tracker_module._estimate_compression_savings_usd("gpt-4o", 100) == 0.0
-    )
+    assert savings_tracker_module._estimate_compression_savings_usd("gpt-4o", 100) == 0.0
     assert savings_tracker_module._estimate_input_cost_usd("gpt-4o", 100) == 0.0
 
     monkeypatch.setattr(
@@ -264,19 +254,11 @@ def test_litellm_resolution_and_savings_estimation_fallbacks(monkeypatch):
         "cost_per_token",
         lambda **kwargs: (_ for _ in ()).throw(RuntimeError("boom")),
     )
-    assert (
-        savings_tracker_module._resolve_litellm_model("mystery-model")
-        == "mystery-model"
-    )
-    assert (
-        savings_tracker_module._estimate_compression_savings_usd("mystery-model", 100)
-        == 0.0
-    )
+    assert savings_tracker_module._resolve_litellm_model("mystery-model") == "mystery-model"
+    assert savings_tracker_module._estimate_compression_savings_usd("mystery-model", 100) == 0.0
 
     monkeypatch.setattr(savings_tracker_module, "LITELLM_AVAILABLE", False)
-    assert (
-        savings_tracker_module._estimate_compression_savings_usd("gpt-4o", 100) == 0.0
-    )
+    assert savings_tracker_module._estimate_compression_savings_usd("gpt-4o", 100) == 0.0
     assert savings_tracker_module._estimate_input_cost_usd("gpt-4o", 100) == 0.0
 
 
@@ -331,10 +313,7 @@ def test_display_session_rolls_after_inactivity_and_counts_zero_savings_requests
         "_utc_now",
         lambda: datetime(2026, 3, 27, 9, 45, tzinfo=timezone.utc),
     )
-    assert (
-        tracker.snapshot()["display_session"]
-        == savings_tracker_module._empty_display_session()
-    )
+    assert tracker.snapshot()["display_session"] == savings_tracker_module._empty_display_session()
 
     tracker.record_request(
         model="gpt-4o",
@@ -362,9 +341,7 @@ def test_display_session_rolls_after_inactivity_and_counts_zero_savings_requests
     }
 
 
-def test_savings_tracker_rollups_preserve_spend_and_input_history(
-    tmp_path, monkeypatch
-):
+def test_savings_tracker_rollups_preserve_spend_and_input_history(tmp_path, monkeypatch):
     path = tmp_path / "proxy_savings.json"
     tracker = SavingsTracker(
         path=str(path),
@@ -507,9 +484,7 @@ def test_savings_tracker_rollups_preserve_spend_and_input_history(
     ]
 
 
-def test_stats_history_persists_across_restarts_and_stats_stays_compatible(
-    tmp_path, monkeypatch
-):
+def test_stats_history_persists_across_restarts_and_stats_stays_compatible(tmp_path, monkeypatch):
     savings_path = tmp_path / "proxy_savings.json"
     monkeypatch.setenv("HEADROOM_SAVINGS_PATH", str(savings_path))
     monkeypatch.setattr(
@@ -555,14 +530,13 @@ def test_stats_history_persists_across_restarts_and_stats_stays_compatible(
         ]
         assert history_data["exports"]["available_series"][-2:] == ["weekly", "monthly"]
         assert history_data["series"]["hourly"][0]["total_input_tokens_delta"] == 120
-        assert history_data["series"]["hourly"][0][
-            "total_input_cost_usd_delta"
-        ] == pytest.approx(0.24)
+        assert history_data["series"]["hourly"][0]["total_input_cost_usd_delta"] == pytest.approx(
+            0.24
+        )
 
         assert stats_data["display_session"] == history_data["display_session"]
         assert (
-            stats_data["persistent_savings"]["display_session"]
-            == history_data["display_session"]
+            stats_data["persistent_savings"]["display_session"] == history_data["display_session"]
         )
 
     with TestClient(create_app(config)) as client:
@@ -584,9 +558,7 @@ def test_stats_history_persists_across_restarts_and_stats_stays_compatible(
         assert updated["display_session"]["total_input_tokens"] == 240
         assert updated["display_session"]["savings_percent"] == pytest.approx(18.64)
         assert updated["series"]["daily"][0]["total_input_tokens_delta"] == 240
-        assert updated["series"]["daily"][0][
-            "total_input_cost_usd_delta"
-        ] == pytest.approx(0.48)
+        assert updated["series"]["daily"][0]["total_input_cost_usd_delta"] == pytest.approx(0.48)
 
         persisted = json.loads(savings_path.read_text())
         assert persisted["lifetime"]["tokens_saved"] == 55