feat: add grid level suggestions

tests/test_grid_levels.py

@@ -0,0 +1,69 @@
+from decimal import Decimal
+
+import pytest
+
+from grid_trading.domain.grid_levels import generate_grid_levels
+
+
+def test_generate_grid_levels_compounds_percentage_spacing_and_rounds_values():
+    levels = generate_grid_levels(
+        current_price=Decimal("10.00"),
+        spacing=Decimal("0.03"),
+        amount_per_grid=Decimal("10000"),
+        lot_size=100,
+        levels=3,
+    )
+
+    assert [item.level for item in levels] == [1, 2, 3]
+    assert [item.buy_price for item in levels] == [Decimal("9.70"), Decimal("9.41"), Decimal("9.13")]
+    assert [item.buy_amount for item in levels] == [Decimal("10000.00")] * 3
+    assert [item.suggested_quantity for item in levels] == [1000, 1000, 1000]
+    assert [item.actual_investment for item in levels] == [
+        Decimal("9700.00"),
+        Decimal("9410.00"),
+        Decimal("9130.00"),
+    ]
+    assert [item.sell_price for item in levels] == [Decimal("9.99"), Decimal("9.69"), Decimal("9.40")]
+    assert [item.estimated_gross_profit for item in levels] == [
+        Decimal("290.00"),
+        Decimal("280.00"),
+        Decimal("270.00"),
+    ]
+
+
+def test_generate_grid_levels_uses_zero_quantity_when_amount_cannot_buy_one_lot():
+    [level] = generate_grid_levels(
+        current_price=Decimal("10.00"),
+        spacing=Decimal("0.03"),
+        amount_per_grid=Decimal("500"),
+        lot_size=100,
+        levels=1,
+    )
+
+    assert level.buy_price == Decimal("9.70")
+    assert level.suggested_quantity == 0
+    assert level.actual_investment == Decimal("0.00")
+    assert level.estimated_gross_profit == Decimal("0.00")
+
+
+@pytest.mark.parametrize(
+    ("current_price", "spacing", "amount_per_grid", "lot_size", "levels"),
+    [
+        (Decimal("0"), Decimal("0.03"), Decimal("10000"), 100, 10),
+        (Decimal("10"), Decimal("0"), Decimal("10000"), 100, 10),
+        (Decimal("10"), Decimal("1"), Decimal("10000"), 100, 10),
+        (Decimal("10"), Decimal("0.03"), Decimal("0"), 100, 10),
+        (Decimal("10"), Decimal("0.03"), Decimal("10000"), 0, 10),
+        (Decimal("10"), Decimal("0.03"), Decimal("10000"), 100, 0),
+        (Decimal("10"), Decimal("0.03"), Decimal("10000"), 100, 101),
+    ],
+)
+def test_generate_grid_levels_validates_inputs(current_price, spacing, amount_per_grid, lot_size, levels):
+    with pytest.raises(ValueError):
+        generate_grid_levels(
+            current_price=current_price,
+            spacing=spacing,
+            amount_per_grid=amount_per_grid,
+            lot_size=lot_size,
+            levels=levels,
+        )

tests/test_services.py

@@ -223,3 +223,38 @@ def test_service_refresh_quotes_uses_realtime_price_in_summaries(tmp_path):
     assert position.current_price == Decimal("4.12")
     assert position.price_source == "tencent"
     assert summary.market_value == Decimal("4120.00")
+
+
+def test_service_generates_grid_level_suggestions_from_realtime_price(tmp_path):
+    service = TradingService(tmp_path / "grid.db", quote_provider=FakeQuoteProvider())
+    service.ensure_defaults()
+    account = service.get_active_account()
+    instrument = service.add_instrument(Instrument(id=None, code="510300", name="沪深300ETF", market="ETF"))
+    service.save_trade(
+        Trade(
+            id=None,
+            account_id=account.id,
+            instrument_id=instrument.id,
+            trade_date=date(2026, 7, 7),
+            side=TradeSide.BUY,
+            price=Decimal("4.00"),
+            quantity=1000,
+            trade_group=TradeGroup.BASE,
+        )
+    )
+    service.refresh_quotes()
+
+    levels = service.get_grid_level_suggestions(instrument.id, levels=2)
+
+    assert [item.buy_price for item in levels] == [Decimal("4.00"), Decimal("3.88")]
+    assert [item.sell_price for item in levels] == [Decimal("4.12"), Decimal("4.00")]
+    assert [item.buy_amount for item in levels] == [Decimal("5000.00"), Decimal("5000.00")]
+    assert [item.suggested_quantity for item in levels] == [1200, 1200]
+
+
+def test_service_returns_empty_grid_levels_without_realtime_price(tmp_path):
+    service = TradingService(tmp_path / "grid.db")
+    service.ensure_defaults()
+    instrument = service.add_instrument(Instrument(id=None, code="510300", name="沪深300ETF", market="ETF"))
+
+    assert service.get_grid_level_suggestions(instrument.id, levels=10) == []

tests/test_ui.py

@@ -35,6 +35,26 @@ def test_main_window_can_be_constructed_offscreen(tmp_path, monkeypatch):
     app.processEvents()
 
 
+def test_main_window_contains_grid_level_table(tmp_path, monkeypatch):
+    monkeypatch.setenv("QT_QPA_PLATFORM", "offscreen")
+
+    from PySide6.QtWidgets import QApplication, QGroupBox
+
+    from grid_trading.services.trading_service import TradingService
+    from grid_trading.ui.main_window import MainWindow
+
+    app = QApplication.instance() or QApplication([])
+    service = TradingService(tmp_path / "grid.db")
+    window = MainWindow(service)
+
+    assert window.grid_levels_table.columnCount() == 7
+    assert any(group.title() == "网格档位" for group in window.findChildren(QGroupBox))
+
+    window.close()
+    service.close()
+    app.processEvents()
+
+
 def test_instrument_dialog_does_not_collect_manual_current_price(monkeypatch):
     monkeypatch.setenv("QT_QPA_PLATFORM", "offscreen")