fix: address pre-push review findings

tests/test_backtest_statistics.py

@@ -43,3 +43,19 @@ def test_backtest_brackets_publish_bootstrap_confidence_intervals():
     assert stats["median_90d"] == 2.5
     assert stats["win_rate_90d"] == 50.0
     assert stats["avg_90d_ci_low"] <= stats["avg_90d"] <= stats["avg_90d_ci_high"]
+
+
+def test_long_horizon_returns_use_a_matching_dependence_block(monkeypatch):
+    observed = {}
+
+    def fake_summary(values, *, block_size, n_resamples):
+        observed.update(block_size=block_size, n_resamples=n_resamples)
+        return {
+            "mean": 1.0, "median": 1.0, "win_rate": 100.0,
+            "mean_ci_low": 0.5, "mean_ci_high": 1.5, "n": len(values),
+        }
+
+    monkeypatch.setattr(engine, "summarize_returns", fake_summary)
+    engine._add_return_statistics({}, "365d", [1.0] * 500)
+
+    assert observed == {"block_size": 365, "n_resamples": 400}