fix(examples): use real backtest-harness API in adapter example/test

examples/backtest_adapter.py

@@ -1,32 +1,43 @@
 """Use the installed backtest-harness package through its public API.
 
 This example intentionally has no sibling-path or ``sys.path`` fallback. Install
-the dependency first, then run the example from this repository.
+the dependency first, then run the example from this repository::
+
+    uv pip install -e ../verdict-backtest
+    uv run python examples/backtest_adapter.py
 """
 
 from __future__ import annotations
 
-from backtest_harness import MonteCarloSimulator, load_kalshi_sample_trades, tearsheet
+from backtest_harness import run_counterfactual
+
+# Small illustrative per-trade return series (fractions). Synthetic, not market data.
+SAMPLE_RETURNS = (0.04, -0.02, 0.03, -0.05, 0.06, 0.01, -0.03, 0.05, -0.01, 0.02, 0.03, -0.04)
 
 
 def main() -> None:
     """Print a small deterministic report from the installed backtest package."""
-    returns, provenance = load_kalshi_sample_trades()
-    stats = MonteCarloSimulator.simulate_equity_paths(
-        trade_returns_pct=returns,
+    evidence = run_counterfactual(
+        run_id="strategy-adapter-example",
+        trade_returns=SAMPLE_RETURNS,
         starting_equity=1_000.0,
-        num_simulations=1_000,
-        trades_per_sim=returns.size,
         seed=20_260_713,
+        dataset_ref="synthetic:strategy-example-v1",
+        num_simulations=1_000,
+        trades_per_sim=len(SAMPLE_RETURNS),
+        walk_forward_splits=3,
     )
-    summary = tearsheet(returns)
-    assert summary is not None
+    results = evidence["results"]
+    monte_carlo = results["monte_carlo"]
 
     print("Installed backtest-harness adapter")
-    print(f"  Fixture: {provenance['name']}")
-    print(f"  P50 final equity: ${stats['p50_equity']:.2f}")
-    print(f"  Risk of ruin: {stats['prob_ruin']:.2%}")
-    print(f"  Max drawdown: {summary['max_drawdown']:.2%}")
+    print(
+        f"  Provider: {evidence['receipt']['provider']} {evidence['receipt']['provider_version']}"
+    )
+    print(f"  P50 final equity: ${monte_carlo['p50_equity']:.2f}")
+    print(f"  Risk of ruin: {monte_carlo['prob_ruin']:.2%}")
+    print(f"  Max drawdown: {results['tearsheet']['max_drawdown']:.2%}")
+    print(f"  Results hash: {evidence['results_hash']}")
 
 
 if __name__ == "__main__":

tests/integration/test_backtest_adapter.py

@@ -2,19 +2,36 @@
 
 import pytest
 
+SAMPLE_RETURNS = (0.04, -0.02, 0.03, -0.05, 0.06, 0.01, -0.03, 0.05, -0.01, 0.02, 0.03, -0.04)
 
-@pytest.mark.integration
-def test_backtest_harness_public_adapter() -> None:
-    """Use only the installed package surface when the sibling package is present."""
+
+def _run(seed: int) -> dict:
     backtest_harness = pytest.importorskip("backtest_harness")
-    returns, provenance = backtest_harness.load_kalshi_sample_trades()
-    stats = backtest_harness.MonteCarloSimulator.simulate_equity_paths(
-        trade_returns_pct=returns,
+    return backtest_harness.run_counterfactual(
+        run_id="strategy-adapter",
+        trade_returns=SAMPLE_RETURNS,
         starting_equity=1_000.0,
+        seed=seed,
+        dataset_ref="synthetic:strategy-adapter-v1",
         num_simulations=100,
-        trades_per_sim=returns.size,
-        seed=20_260_713,
+        trades_per_sim=len(SAMPLE_RETURNS),
+        walk_forward_splits=3,
     )
 
-    assert provenance["source"] == "synthetic"
-    assert stats["used_numba"] is True
+
+@pytest.mark.integration
+def test_backtest_harness_public_adapter() -> None:
+    """Use only the installed package surface when the sibling package is present."""
+    evidence = _run(seed=20_260_713)
+
+    assert evidence["receipt"]["provider"] == "verdict-backtest"
+    assert evidence["receipt"]["outcome"] == "success"
+    monte_carlo = evidence["results"]["monte_carlo"]
+    assert monte_carlo["p05_equity"] <= monte_carlo["p50_equity"] <= monte_carlo["p95_equity"]
+    assert 0.0 <= monte_carlo["prob_ruin"] <= 1.0
+
+
+@pytest.mark.integration
+def test_backtest_harness_adapter_is_reproducible() -> None:
+    """The same seed must give the same evidence hash across the package boundary."""
+    assert _run(seed=7)["results_hash"] == _run(seed=7)["results_hash"]