refactor(BT-001C): share historical fixture provider

app/services/backtesting/fixture_source.py

@@ -0,0 +1,97 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from datetime import date
+from enum import StrEnum
+from typing import Any
+
+from app.services.backtesting.historical_provider import DailyClosePoint, SyntheticHistoricalProvider
+
+SEEDED_GLD_2024_FIXTURE_HISTORY: tuple[DailyClosePoint, ...] = (
+    DailyClosePoint(date=date(2024, 1, 2), close=100.0),
+    DailyClosePoint(date=date(2024, 1, 3), close=96.0),
+    DailyClosePoint(date=date(2024, 1, 4), close=92.0),
+    DailyClosePoint(date=date(2024, 1, 5), close=88.0),
+    DailyClosePoint(date=date(2024, 1, 8), close=85.0),
+)
+
+
+class WindowPolicy(StrEnum):
+    EXACT = "exact"
+    BOUNDED = "bounded"
+
+
+@dataclass(frozen=True)
+class SharedHistoricalFixtureSource:
+    feature_label: str
+    supported_symbol: str
+    history: tuple[DailyClosePoint, ...]
+    window_policy: WindowPolicy
+
+    @property
+    def start_date(self) -> date:
+        return self.history[0].date
+
+    @property
+    def end_date(self) -> date:
+        return self.history[-1].date
+
+    def load_daily_closes(self, symbol: str, start_date: date, end_date: date) -> list[DailyClosePoint]:
+        if start_date > end_date:
+            raise ValueError("start_date must be on or before end_date")
+        normalized_symbol = symbol.strip().upper()
+        if normalized_symbol != self.supported_symbol.strip().upper():
+            raise ValueError(
+                f"{self.feature_label} deterministic fixture data only supports {self.supported_symbol} on this page"
+            )
+        if self.window_policy is WindowPolicy.EXACT:
+            if start_date != self.start_date or end_date != self.end_date:
+                raise ValueError(
+                    f"{self.feature_label} deterministic fixture data only supports {self.supported_symbol} "
+                    f"on the seeded {self.start_date.isoformat()} through {self.end_date.isoformat()} window"
+                )
+        else:
+            if start_date < self.start_date or end_date > self.end_date:
+                raise ValueError(
+                    f"{self.feature_label} deterministic fixture data only supports the seeded "
+                    f"{self.start_date.isoformat()} through {self.end_date.isoformat()} window"
+                )
+        return [point for point in self.history if start_date <= point.date <= end_date]
+
+
+class FixtureBoundSyntheticHistoricalProvider:
+    def __init__(self, base_provider: SyntheticHistoricalProvider, source: SharedHistoricalFixtureSource) -> None:
+        self.base_provider = base_provider
+        self.source = source
+
+    def load_history(self, symbol: str, start_date: date, end_date: date) -> list[DailyClosePoint]:
+        rows = self.source.load_daily_closes(symbol, start_date, end_date)
+        return sorted(rows, key=lambda row: row.date)
+
+    def __getattr__(self, name: str) -> Any:
+        return getattr(self.base_provider, name)
+
+
+def build_backtest_ui_fixture_source() -> SharedHistoricalFixtureSource:
+    return SharedHistoricalFixtureSource(
+        feature_label="BT-001A",
+        supported_symbol="GLD",
+        history=SEEDED_GLD_2024_FIXTURE_HISTORY,
+        window_policy=WindowPolicy.EXACT,
+    )
+
+
+def build_event_comparison_fixture_source() -> SharedHistoricalFixtureSource:
+    return SharedHistoricalFixtureSource(
+        feature_label="BT-003A",
+        supported_symbol="GLD",
+        history=SEEDED_GLD_2024_FIXTURE_HISTORY,
+        window_policy=WindowPolicy.BOUNDED,
+    )
+
+
+def bind_fixture_source(
+    base_provider: SyntheticHistoricalProvider,
+    source: SharedHistoricalFixtureSource,
+) -> FixtureBoundSyntheticHistoricalProvider:
+    return FixtureBoundSyntheticHistoricalProvider(base_provider=base_provider, source=source)

app/services/backtesting/ui_service.py

@@ -13,13 +13,7 @@ from app.models.backtest import (
     ProviderRef,
     TemplateRef,
 )
-from app.services.backtesting.historical_provider import (
+from app.services.backtesting.fixture_source import bind_fixture_source, build_backtest_ui_fixture_source
-    DailyClosePoint,
-    HistoricalOptionMark,
-    HistoricalOptionPosition,
-    SyntheticHistoricalProvider,
-    SyntheticOptionQuote,
-)
 from app.services.backtesting.input_normalization import normalize_historical_scenario_inputs
 from app.services.backtesting.service import BacktestService
 from app.services.strategy_templates import StrategyTemplateService
@@ -37,29 +31,6 @@ def _validate_initial_collateral(underlying_units: float, entry_spot: float, loa
         )
 
 
-DETERMINISTIC_UI_FIXTURE_HISTORY: tuple[DailyClosePoint, ...] = (
-    DailyClosePoint(date=date(2024, 1, 2), close=100.0),
-    DailyClosePoint(date=date(2024, 1, 3), close=96.0),
-    DailyClosePoint(date=date(2024, 1, 4), close=92.0),
-    DailyClosePoint(date=date(2024, 1, 5), close=88.0),
-    DailyClosePoint(date=date(2024, 1, 8), close=85.0),
-)
-
-
-class DeterministicBacktestFixtureSource:
-    def load_daily_closes(self, symbol: str, start_date: date, end_date: date) -> list[DailyClosePoint]:
-        normalized_symbol = symbol.strip().upper()
-        if (
-            normalized_symbol != SUPPORTED_BACKTEST_PAGE_SYMBOL
-            or start_date != date(2024, 1, 2)
-            or end_date != date(2024, 1, 8)
-        ):
-            raise ValueError(
-                "BT-001A deterministic fixture data only supports GLD on the seeded 2024-01-02 through 2024-01-08 window"
-            )
-        return list(DETERMINISTIC_UI_FIXTURE_HISTORY)
-
-
 @dataclass(frozen=True)
 class BacktestPageRunResult:
     scenario: BacktestScenario
@@ -67,40 +38,6 @@ class BacktestPageRunResult:
     entry_spot: float
 
 
-class FixtureBoundHistoricalProvider:
-    def __init__(self, base_provider: SyntheticHistoricalProvider) -> None:
-        self.base_provider = base_provider
-        self.source = DeterministicBacktestFixtureSource()
-        self.provider_id = base_provider.provider_id
-        self.pricing_mode = base_provider.pricing_mode
-        self.implied_volatility = base_provider.implied_volatility
-        self.risk_free_rate = base_provider.risk_free_rate
-
-    def load_history(self, symbol: str, start_date: date, end_date: date) -> list[DailyClosePoint]:
-        rows = self.source.load_daily_closes(symbol, start_date, end_date)
-        filtered = [row for row in rows if start_date <= row.date <= end_date]
-        return sorted(filtered, key=lambda row: row.date)
-
-    def validate_provider_ref(self, provider_ref: ProviderRef) -> None:
-        self.base_provider.validate_provider_ref(provider_ref)
-
-    def resolve_expiry(self, trading_days: list[DailyClosePoint], as_of_date: date, target_expiry_days: int) -> date:
-        return self.base_provider.resolve_expiry(trading_days, as_of_date, target_expiry_days)
-
-    def price_option(self, **kwargs: object) -> SyntheticOptionQuote:
-        return self.base_provider.price_option(**kwargs)
-
-    def open_position(self, **kwargs: object) -> HistoricalOptionPosition:
-        return self.base_provider.open_position(**kwargs)
-
-    def mark_position(self, position: HistoricalOptionPosition, **kwargs: object) -> HistoricalOptionMark:
-        return self.base_provider.mark_position(position, **kwargs)
-
-    @staticmethod
-    def intrinsic_value(*, option_type: str, spot: float, strike: float) -> float:
-        return SyntheticHistoricalProvider.intrinsic_value(option_type=option_type, spot=spot, strike=strike)
-
-
 class BacktestPageService:
     def __init__(
         self,
@@ -112,7 +49,7 @@ class BacktestPageService:
             provider=None,
         )
         self.template_service = template_service or base_service.template_service
-        fixture_provider = FixtureBoundHistoricalProvider(base_service.provider)
+        fixture_provider = bind_fixture_source(base_service.provider, build_backtest_ui_fixture_source())
         self.backtest_service = copy(base_service)
         self.backtest_service.provider = fixture_provider
         self.backtest_service.template_service = self.template_service

app/services/event_comparison_ui.py

@@ -1,11 +1,11 @@
 from __future__ import annotations
 
 from dataclasses import dataclass
-from datetime import date
 
 from app.models.backtest import BacktestScenario, EventComparisonRanking, EventComparisonReport
 from app.services.backtesting.comparison import EventComparisonService
-from app.services.backtesting.historical_provider import DailyClosePoint, SyntheticHistoricalProvider
+from app.services.backtesting.fixture_source import bind_fixture_source, build_event_comparison_fixture_source
+from app.services.backtesting.historical_provider import SyntheticHistoricalProvider
 from app.services.backtesting.input_normalization import normalize_historical_scenario_inputs
 from app.services.event_presets import EventPresetService
 from app.services.strategy_templates import StrategyTemplateService
@@ -23,32 +23,7 @@ def _validate_initial_collateral(underlying_units: float, entry_spot: float, loa
         )
 
 
-DETERMINISTIC_EVENT_COMPARISON_FIXTURE_HISTORY: tuple[DailyClosePoint, ...] = (
+EventComparisonFixtureHistoricalPriceSource = build_event_comparison_fixture_source
-    DailyClosePoint(date=date(2024, 1, 2), close=100.0),
-    DailyClosePoint(date=date(2024, 1, 3), close=96.0),
-    DailyClosePoint(date=date(2024, 1, 4), close=92.0),
-    DailyClosePoint(date=date(2024, 1, 5), close=88.0),
-    DailyClosePoint(date=date(2024, 1, 8), close=85.0),
-)
-
-FIXTURE_HISTORY_START = DETERMINISTIC_EVENT_COMPARISON_FIXTURE_HISTORY[0].date
-FIXTURE_HISTORY_END = DETERMINISTIC_EVENT_COMPARISON_FIXTURE_HISTORY[-1].date
-
-
-class EventComparisonFixtureHistoricalPriceSource:
-    def load_daily_closes(self, symbol: str, start_date: date, end_date: date) -> list[DailyClosePoint]:
-        normalized_symbol = symbol.strip().upper()
-        if normalized_symbol != SUPPORTED_EVENT_COMPARISON_SYMBOL:
-            raise ValueError(
-                "BT-003A deterministic fixture data only supports GLD event-comparison presets on this page"
-            )
-        if start_date < FIXTURE_HISTORY_START or end_date > FIXTURE_HISTORY_END:
-            raise ValueError(
-                "BT-003A deterministic fixture data only supports the seeded 2024-01-02 through 2024-01-08 window"
-            )
-        return [
-            point for point in DETERMINISTIC_EVENT_COMPARISON_FIXTURE_HISTORY if start_date <= point.date <= end_date
-        ]
 
 
 @dataclass(frozen=True)
@@ -102,7 +77,10 @@ class EventComparisonPageService:
         self.event_preset_service = event_preset_service or EventPresetService()
         self.template_service = template_service or StrategyTemplateService()
         if comparison_service is None:
-            provider = SyntheticHistoricalProvider(source=EventComparisonFixtureHistoricalPriceSource())
+            provider = bind_fixture_source(
+                SyntheticHistoricalProvider(),
+                build_event_comparison_fixture_source(),
+            )
             comparison_service = EventComparisonService(
                 provider=provider,
                 event_preset_service=self.event_preset_service,

docs/roadmap/ROADMAP.yaml

@@ -13,7 +13,6 @@ notes:
   - Pre-alpha policy: we may cut or replace old features without backward compatibility until alpha is declared.
   - Alpha migration policy: once alpha is declared, compatibility only needs to move forward; backward migrations are not required.
 priority_queue:
-  - BT-001C
   - EXEC-001
   - EXEC-002
   - DATA-002A
@@ -22,6 +21,7 @@ priority_queue:
   - BT-003
   - BT-002A
 recently_completed:
+  - BT-001C
   - BT-002
   - PORT-003
   - BT-003B
@@ -45,7 +45,6 @@ states:
     - EXEC-001
     - EXEC-002
     - BT-003
-    - BT-001C
     - BT-002A
   in_progress: []
   done:
@@ -62,6 +61,7 @@ states:
     - EXEC-001A
     - BT-001
     - BT-001A
+    - BT-001C
     - BT-002
     - BT-003A
     - BT-003B

docs/roadmap/backlog/BT-001C-shared-historical-fixture-provider.yaml

@@ -1,14 +0,0 @@
-id: BT-001C
-title: Shared Historical Fixture/Test Provider Cleanup
-status: backlog
-priority: P2
-effort: S
-depends_on:
-  - BT-001A
-  - BT-003A
-tags: [backtesting, test-infra]
-summary: Centralize deterministic historical fixture logic used by browser-tested backtest UIs.
-acceptance_criteria:
-  - Deterministic historical fixture/provider logic is centralized.
-  - Supported seeded windows are explicit and fail closed outside allowed ranges.
-  - Both /backtests and /event-comparison use the shared deterministic provider.

docs/roadmap/done/BT-001C-shared-historical-fixture-provider.yaml

@@ -0,0 +1,18 @@
+id: BT-001C
+title: Shared Historical Fixture/Test Provider Cleanup
+status: done
+priority: P2
+effort: S
+depends_on:
+  - BT-001A
+  - BT-003A
+tags:
+  - backtesting
+  - test-infra
+summary: Deterministic historical fixture logic for browser-tested backtest UIs is now centralized behind a shared fixture source used by both `/backtests` and `/event-comparison`.
+completed_notes:
+  - Added `app/services/backtesting/fixture_source.py` with shared seeded GLD fixture history and explicit exact-vs-bounded window policies.
+  - Updated `app/services/backtesting/ui_service.py` so the `/backtests` page uses the shared fixture source in exact-window mode and still fails closed outside the seeded BT-001A range.
+  - Updated `app/services/event_comparison_ui.py` so the `/event-comparison` page uses the same shared fixture source in bounded-window mode for preset subranges inside the seeded BT-003A fixture window.
+  - Added focused regression coverage in `tests/test_backtesting_fixture_source.py` proving the shared source enforces exact and bounded policies explicitly and that both page services use the centralized fixture source.
+  - During this implementation loop, local Docker validation stayed green on the affected historical routes: `/health` returned OK and `tests/test_e2e_playwright.py` passed against the Docker-served app.

tests/test_backtest_ui.py

@@ -282,3 +282,39 @@ def test_backtest_page_service_uses_injected_provider_identity_in_provider_ref()
 
     assert result.scenario.provider_ref.provider_id == "custom_v1"
     assert result.scenario.provider_ref.pricing_mode == "custom_mode"
+
+
+def test_backtest_page_service_preserves_injected_provider_behavior_beyond_history_loading() -> None:
+    class CustomProvider(SyntheticHistoricalProvider):
+        provider_id = "custom_v2"
+        pricing_mode = "custom_mode"
+
+        def price_option_by_type(self, **kwargs: object):
+            quote = super().price_option_by_type(**kwargs)
+            return quote.__class__(
+                position_id=quote.position_id,
+                leg_id=quote.leg_id,
+                spot=quote.spot,
+                strike=quote.strike,
+                expiry=quote.expiry,
+                quantity=quote.quantity,
+                mark=42.0,
+            )
+
+    provider = CustomProvider(source=StaticBacktestSource(), implied_volatility=0.2, risk_free_rate=0.01)
+    injected_service = BacktestService(provider=provider)
+    page_service = BacktestPageService(backtest_service=injected_service)
+
+    result = page_service.run_read_only_scenario(
+        symbol="GLD",
+        start_date=date(2024, 1, 2),
+        end_date=date(2024, 1, 8),
+        template_slug="protective-put-atm-12m",
+        underlying_units=1000.0,
+        loan_amount=68000.0,
+        margin_call_ltv=0.75,
+    )
+
+    template_result = result.run_result.template_results[0]
+    assert template_result.daily_path[0].option_market_value == 42000.0
+    assert template_result.summary_metrics.total_hedge_cost == 42000.0

tests/test_backtesting_fixture_source.py

@@ -0,0 +1,74 @@
+from __future__ import annotations
+
+from datetime import date
+
+import pytest
+
+from app.services.backtesting.fixture_source import (
+    SEEDED_GLD_2024_FIXTURE_HISTORY,
+    SharedHistoricalFixtureSource,
+    WindowPolicy,
+)
+from app.services.backtesting.ui_service import BacktestPageService
+from app.services.event_comparison_ui import EventComparisonPageService
+
+
+def test_shared_fixture_source_exact_window_requires_seeded_bounds() -> None:
+    source = SharedHistoricalFixtureSource(
+        feature_label="BT-001A",
+        supported_symbol="GLD",
+        history=SEEDED_GLD_2024_FIXTURE_HISTORY,
+        window_policy=WindowPolicy.EXACT,
+    )
+
+    rows = source.load_daily_closes("GLD", date(2024, 1, 2), date(2024, 1, 8))
+
+    assert [row.date.isoformat() for row in rows] == [
+        "2024-01-02",
+        "2024-01-03",
+        "2024-01-04",
+        "2024-01-05",
+        "2024-01-08",
+    ]
+
+    with pytest.raises(ValueError, match="seeded 2024-01-02 through 2024-01-08 window"):
+        source.load_daily_closes("GLD", date(2024, 1, 3), date(2024, 1, 8))
+
+
+def test_shared_fixture_source_bounded_window_allows_subranges_but_fails_closed_outside_seeded_bounds() -> None:
+    source = SharedHistoricalFixtureSource(
+        feature_label="BT-003A",
+        supported_symbol="GLD",
+        history=SEEDED_GLD_2024_FIXTURE_HISTORY,
+        window_policy=WindowPolicy.BOUNDED,
+    )
+
+    rows = source.load_daily_closes("GLD", date(2024, 1, 3), date(2024, 1, 5))
+
+    assert [row.date.isoformat() for row in rows] == ["2024-01-03", "2024-01-04", "2024-01-05"]
+
+    with pytest.raises(ValueError, match="seeded 2024-01-02 through 2024-01-08 window"):
+        source.load_daily_closes("GLD", date(2024, 1, 1), date(2024, 1, 8))
+
+    with pytest.raises(ValueError, match="start_date must be on or before end_date"):
+        source.load_daily_closes("GLD", date(2024, 1, 5), date(2024, 1, 3))
+
+
+def test_backtest_page_service_uses_shared_exact_fixture_source() -> None:
+    service = BacktestPageService()
+
+    source = service.backtest_service.provider.source
+
+    assert isinstance(source, SharedHistoricalFixtureSource)
+    assert source.feature_label == "BT-001A"
+    assert source.window_policy is WindowPolicy.EXACT
+
+
+def test_event_comparison_page_service_uses_shared_bounded_fixture_source() -> None:
+    service = EventComparisonPageService()
+
+    source = service.comparison_service.provider.source
+
+    assert isinstance(source, SharedHistoricalFixtureSource)
+    assert source.feature_label == "BT-003A"
+    assert source.window_policy is WindowPolicy.BOUNDED