tests: add explicit test for stake_amount_filled

tests/persistence/test_persistence.py

@@ -2683,6 +2683,36 @@ def test_select_filled_orders(fee):
     assert len(orders) == 0
 
 
+@pytest.mark.usefixtures("init_persistence")
+def test_select_filled_orders_usdt(fee):
+    create_mock_trades_usdt(fee)
+
+    trades = Trade.get_trades().all()
+
+    # Closed buy order, no sell order
+    orders = trades[0].select_filled_orders("buy")
+    assert isinstance(orders, list)
+    assert len(orders) == 1
+    assert orders[0].amount == 2.0
+    assert orders[0].filled == 2.0
+    assert orders[0].side == "buy"
+    assert orders[0].price == 10.0
+    assert orders[0].stake_amount == 20
+    assert orders[0].stake_amount_filled == 20
+
+    orders = trades[3].select_filled_orders("buy")
+    assert isinstance(orders, list)
+    assert len(orders) == 0
+    orders = trades[3].select_filled_or_open_orders()
+    assert isinstance(orders, list)
+    assert len(orders) == 1
+    assert orders[0].price == 2.0
+    assert orders[0].amount == 10
+    assert orders[0].filled == 0
+    assert orders[0].stake_amount == 20
+    assert orders[0].stake_amount_filled == 0
+
+
 @pytest.mark.usefixtures("init_persistence")
 def test_order_to_ccxt(limit_buy_order_open, limit_sell_order_usdt_open):
     order = Order.parse_from_ccxt_object(limit_buy_order_open, "mocked", "buy")