test: reproduce execution cash and long-only violations

tests/test_execution.py

@@ -405,6 +405,49 @@ def test_simulate_multi_day_with_audit_records_costs_without_replay():
     assert result.daily_executions[1].executions == ()
 
 
+def test_simulate_multi_day_with_audit_never_spends_more_cash_than_available():
+    """满仓目标应按可用现金部分成交，不能用负现金隐式加杠杆。"""
+    result = simulate_multi_day_with_audit(
+        [("d1", {"A": 1.0})],
+        [("d1", {"A": 10.0})],
+        1_000.0,
+    )
+
+    execution = result.daily_executions[0].executions[0]
+    assert result.positions[0].cash >= -1e-9
+    assert 0 < execution.partial_fill_pct < 1
+    assert execution.blocked_reason == "insufficient_cash_partial_fill"
+    assert result.final_portfolio_value == pytest.approx(1_000.0 - result.total_costs)
+
+
+@pytest.mark.parametrize(
+    "targets",
+    [
+        {"A": -0.1},
+        {"A": 0.6, "B": 0.5},
+        {"A": float("nan")},
+    ],
+)
+def test_simulate_multi_day_with_audit_rejects_invalid_long_only_weights(targets):
+    """多日 A 股目标必须是有限、非负且合计不超过 100% 的权重。"""
+    with pytest.raises(ValueError, match="target weights"):
+        simulate_multi_day_with_audit(
+            [("d1", targets)],
+            [("d1", {"A": 10.0, "B": 10.0})],
+            1_000.0,
+        )
+
+
+def test_simulate_multi_day_with_audit_requires_price_for_existing_holding():
+    """已有持仓缺价时无法可信估值，必须失败而不是把市值记为零。"""
+    with pytest.raises(ValueError, match="missing price for held asset A"):
+        simulate_multi_day_with_audit(
+            [("d1", {"A": 1.0}), ("d2", {"A": 1.0})],
+            [("d1", {"A": 10.0}), ("d2", {})],
+            1_000.0,
+        )
+
+
 def test_simulate_multi_day_with_audit_records_unpriced_target_rejection():
     """缺失价格的目标不能吞掉现金，且必须留下拒绝原因。"""
     result = simulate_multi_day_with_audit(