fix: domestic current price fetching and KRX tick unit rounding (#157)

**Problem 1 — Current price always 0**
get_orderbook() used inquire-asking-price-exp-ccn which has no stck_prpr
in output1 (only askp/bidp data). This caused every domestic BUY to be
skipped with "no affordable quantity (cash=..., price=0.00)".

**Problem 2 — KRX tick unit error on limit orders**
Limit order prices were passed unrounded, triggering 호가단위 오류 in VTS.
Also ORD_DVSN was wrongly set to "01" (시장가) for limit orders.

**Fix**
- Add kr_tick_unit(price) and kr_round_down(price) module-level helpers
  implementing KRX 7-tier price tick rules (1/5/10/50/100/500/1000원).
- Add get_current_price(stock_code) → (price, change_pct, foreigner_net)
  using FHKST01010100 / inquire-price API (works in VTS, returns correct
  stck_prpr, prdy_ctrt, frgn_ntby_qty).
- Fix send_order() ORD_DVSN: "00"=지정가, "01"=시장가 (was "01"/"06").
- Apply kr_round_down() to limit order price inside send_order().
- Replace both get_orderbook() calls in main.py with get_current_price().
- Update all 4 test_main.py mock sites to use get_current_price AsyncMock.

**Tests added** (25 new tests, all 646 pass)
- TestKrTickUnit: 13 parametrized boundary cases + 7 round-down cases
- TestGetCurrentPrice: correct fields, correct API path/TR_ID, HTTP error
- TestSendOrderTickRounding: tick rounding, ORD_DVSN 00/01

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/broker/kis_api.py

@@ -20,6 +20,39 @@ _KIS_VTS_HOST = "openapivts.koreainvestment.com"
 logger = logging.getLogger(__name__)
 
 
+def kr_tick_unit(price: float) -> int:
+    """Return KRX tick size for the given price level.
+
+    KRX price tick rules (domestic stocks):
+        price < 2,000        →   1원
+        2,000  ≤ price < 5,000     →   5원
+        5,000  ≤ price < 20,000    →  10원
+        20,000 ≤ price < 50,000    →  50원
+        50,000 ≤ price < 200,000   → 100원
+        200,000 ≤ price < 500,000  → 500원
+        500,000 ≤ price            → 1,000원
+    """
+    if price < 2_000:
+        return 1
+    if price < 5_000:
+        return 5
+    if price < 20_000:
+        return 10
+    if price < 50_000:
+        return 50
+    if price < 200_000:
+        return 100
+    if price < 500_000:
+        return 500
+    return 1_000
+
+
+def kr_round_down(price: float) -> int:
+    """Round *down* price to the nearest KRX tick unit."""
+    tick = kr_tick_unit(price)
+    return int(price // tick * tick)
+
+
 class LeakyBucket:
     """Simple leaky-bucket rate limiter for async code."""
 
@@ -198,6 +231,55 @@ class KISBroker:
         except (TimeoutError, aiohttp.ClientError) as exc:
             raise ConnectionError(f"Network error fetching orderbook: {exc}") from exc
 
+    async def get_current_price(
+        self, stock_code: str
+    ) -> tuple[float, float, float]:
+        """Fetch current price data for a domestic stock.
+
+        Uses the ``inquire-price`` API (FHKST01010100), which works in both
+        real and VTS environments and returns the actual last-traded price.
+
+        Returns:
+            (current_price, prdy_ctrt, frgn_ntby_qty)
+            - current_price: Last traded price in KRW.
+            - prdy_ctrt: Day change rate (%).
+            - frgn_ntby_qty: Foreigner net buy quantity.
+        """
+        await self._rate_limiter.acquire()
+        session = self._get_session()
+
+        headers = await self._auth_headers("FHKST01010100")
+        params = {
+            "FID_COND_MRKT_DIV_CODE": "J",
+            "FID_INPUT_ISCD": stock_code,
+        }
+        url = f"{self._base_url}/uapi/domestic-stock/v1/quotations/inquire-price"
+
+        def _f(val: str | None) -> float:
+            try:
+                return float(val or "0")
+            except ValueError:
+                return 0.0
+
+        try:
+            async with session.get(url, headers=headers, params=params) as resp:
+                if resp.status != 200:
+                    text = await resp.text()
+                    raise ConnectionError(
+                        f"get_current_price failed ({resp.status}): {text}"
+                    )
+                data = await resp.json()
+                out = data.get("output", {})
+                return (
+                    _f(out.get("stck_prpr")),
+                    _f(out.get("prdy_ctrt")),
+                    _f(out.get("frgn_ntby_qty")),
+                )
+        except (TimeoutError, aiohttp.ClientError) as exc:
+            raise ConnectionError(
+                f"Network error fetching current price: {exc}"
+            ) from exc
+
     async def get_balance(self) -> dict[str, Any]:
         """Fetch current account balance and holdings."""
         await self._rate_limiter.acquire()
@@ -249,13 +331,23 @@ class KISBroker:
         session = self._get_session()
 
         tr_id = "VTTC0802U" if order_type == "BUY" else "VTTC0801U"
+
+        # KRX requires limit orders to be rounded down to the tick unit.
+        # ORD_DVSN: "00"=지정가, "01"=시장가
+        if price > 0:
+            ord_dvsn = "00"  # 지정가
+            ord_price = kr_round_down(price)
+        else:
+            ord_dvsn = "01"  # 시장가
+            ord_price = 0
+
         body = {
             "CANO": self._account_no,
             "ACNT_PRDT_CD": self._product_cd,
             "PDNO": stock_code,
-            "ORD_DVSN": "01" if price > 0 else "06",  # 01=지정가, 06=시장가
+            "ORD_DVSN": ord_dvsn,
             "ORD_QTY": str(quantity),
-            "ORD_UNPR": str(price),
+            "ORD_UNPR": str(ord_price),
         }
 
         hash_key = await self._get_hash_key(body)

src/main.py

@@ -204,7 +204,9 @@ async def trading_cycle(
 
     # 1. Fetch market data
     if market.is_domestic:
-        orderbook = await broker.get_orderbook(stock_code)
+        current_price, price_change_pct, foreigner_net = await broker.get_current_price(
+            stock_code
+        )
         balance_data = await broker.get_balance()
 
         output2 = balance_data.get("output2", [{}])
@@ -215,10 +217,6 @@ async def trading_cycle(
             else "0"
         )
         purchase_total = safe_float(output2[0].get("pchs_amt_smtl_amt", "0")) if output2 else 0
-
-        current_price = safe_float(orderbook.get("output1", {}).get("stck_prpr", "0"))
-        foreigner_net = safe_float(orderbook.get("output1", {}).get("frgn_ntby_qty", "0"))
-        price_change_pct = safe_float(orderbook.get("output1", {}).get("prdy_ctrt", "0"))
     else:
         # Overseas market
         price_data = await overseas_broker.get_overseas_price(
@@ -726,15 +724,8 @@ async def run_daily_session(
         for stock_code in watchlist:
             try:
                 if market.is_domestic:
-                    orderbook = await broker.get_orderbook(stock_code)
-                    current_price = safe_float(
-                        orderbook.get("output1", {}).get("stck_prpr", "0")
-                    )
-                    foreigner_net = safe_float(
-                        orderbook.get("output1", {}).get("frgn_ntby_qty", "0")
-                    )
-                    price_change_pct = safe_float(
-                        orderbook.get("output1", {}).get("prdy_ctrt", "0")
+                    current_price, price_change_pct, foreigner_net = (
+                        await broker.get_current_price(stock_code)
                     )
                 else:
                     price_data = await overseas_broker.get_overseas_price(

tests/test_broker.py

@@ -375,3 +375,201 @@ class TestFetchMarketRankings:
         assert result[0]["stock_code"] == "005930"
         assert result[0]["price"] == 75000.0
         assert result[0]["change_rate"] == 2.5
+
+
+# ---------------------------------------------------------------------------
+# KRX tick unit / round-down helpers (issue #157)
+# ---------------------------------------------------------------------------
+
+
+from src.broker.kis_api import kr_tick_unit, kr_round_down  # noqa: E402
+
+
+class TestKrTickUnit:
+    """kr_tick_unit and kr_round_down must implement KRX price tick rules."""
+
+    @pytest.mark.parametrize(
+        "price, expected_tick",
+        [
+            (1999, 1),
+            (2000, 5),
+            (4999, 5),
+            (5000, 10),
+            (19999, 10),
+            (20000, 50),
+            (49999, 50),
+            (50000, 100),
+            (199999, 100),
+            (200000, 500),
+            (499999, 500),
+            (500000, 1000),
+            (1000000, 1000),
+        ],
+    )
+    def test_tick_unit_boundaries(self, price: int, expected_tick: int) -> None:
+        assert kr_tick_unit(price) == expected_tick
+
+    @pytest.mark.parametrize(
+        "price, expected_rounded",
+        [
+            (188150, 188100),   # 100원 단위, 50원 잔여 → 내림
+            (188100, 188100),   # 이미 정렬됨
+            (75050, 75000),     # 100원 단위, 50원 잔여 → 내림
+            (49950, 49950),     # 50원 단위 정렬됨
+            (49960, 49950),     # 50원 단위, 10원 잔여 → 내림
+            (1999, 1999),       # 1원 단위 → 그대로
+            (5003, 5000),       # 10원 단위, 3원 잔여 → 내림
+        ],
+    )
+    def test_round_down_to_tick(self, price: int, expected_rounded: int) -> None:
+        assert kr_round_down(price) == expected_rounded
+
+
+# ---------------------------------------------------------------------------
+# get_current_price (issue #157)
+# ---------------------------------------------------------------------------
+
+
+class TestGetCurrentPrice:
+    """get_current_price must use inquire-price API and return (price, change, foreigner)."""
+
+    @pytest.fixture
+    def broker(self, settings) -> KISBroker:
+        b = KISBroker(settings)
+        b._access_token = "tok"
+        b._token_expires_at = float("inf")
+        b._rate_limiter.acquire = AsyncMock()
+        return b
+
+    @pytest.mark.asyncio
+    async def test_returns_correct_fields(self, broker: KISBroker) -> None:
+        mock_resp = AsyncMock()
+        mock_resp.status = 200
+        mock_resp.json = AsyncMock(
+            return_value={
+                "rt_cd": "0",
+                "output": {
+                    "stck_prpr": "188600",
+                    "prdy_ctrt": "3.97",
+                    "frgn_ntby_qty": "12345",
+                },
+            }
+        )
+        mock_resp.__aenter__ = AsyncMock(return_value=mock_resp)
+        mock_resp.__aexit__ = AsyncMock(return_value=False)
+
+        with patch("aiohttp.ClientSession.get", return_value=mock_resp) as mock_get:
+            price, change_pct, foreigner = await broker.get_current_price("005930")
+
+        assert price == 188600.0
+        assert change_pct == 3.97
+        assert foreigner == 12345.0
+
+        call_kwargs = mock_get.call_args
+        url = call_kwargs[0][0] if call_kwargs[0] else call_kwargs[1].get("url", "")
+        headers = call_kwargs[1].get("headers", {})
+        assert "inquire-price" in url
+        assert headers.get("tr_id") == "FHKST01010100"
+
+    @pytest.mark.asyncio
+    async def test_http_error_raises_connection_error(self, broker: KISBroker) -> None:
+        mock_resp = AsyncMock()
+        mock_resp.status = 500
+        mock_resp.text = AsyncMock(return_value="Internal Server Error")
+        mock_resp.__aenter__ = AsyncMock(return_value=mock_resp)
+        mock_resp.__aexit__ = AsyncMock(return_value=False)
+
+        with patch("aiohttp.ClientSession.get", return_value=mock_resp):
+            with pytest.raises(ConnectionError, match="get_current_price failed"):
+                await broker.get_current_price("005930")
+
+
+# ---------------------------------------------------------------------------
+# send_order tick rounding and ORD_DVSN (issue #157)
+# ---------------------------------------------------------------------------
+
+
+class TestSendOrderTickRounding:
+    """send_order must apply KRX tick rounding and correct ORD_DVSN codes."""
+
+    @pytest.fixture
+    def broker(self, settings) -> KISBroker:
+        b = KISBroker(settings)
+        b._access_token = "tok"
+        b._token_expires_at = float("inf")
+        b._rate_limiter.acquire = AsyncMock()
+        return b
+
+    @pytest.mark.asyncio
+    async def test_limit_order_rounds_down_to_tick(self, broker: KISBroker) -> None:
+        """Price 188150 (not on 100-won tick) must be rounded to 188100."""
+        mock_hash = AsyncMock()
+        mock_hash.status = 200
+        mock_hash.json = AsyncMock(return_value={"HASH": "h"})
+        mock_hash.__aenter__ = AsyncMock(return_value=mock_hash)
+        mock_hash.__aexit__ = AsyncMock(return_value=False)
+
+        mock_order = AsyncMock()
+        mock_order.status = 200
+        mock_order.json = AsyncMock(return_value={"rt_cd": "0"})
+        mock_order.__aenter__ = AsyncMock(return_value=mock_order)
+        mock_order.__aexit__ = AsyncMock(return_value=False)
+
+        with patch(
+            "aiohttp.ClientSession.post", side_effect=[mock_hash, mock_order]
+        ) as mock_post:
+            await broker.send_order("005930", "BUY", 1, price=188150)
+
+        order_call = mock_post.call_args_list[1]
+        body = order_call[1].get("json", {})
+        assert body["ORD_UNPR"] == "188100"  # rounded down
+        assert body["ORD_DVSN"] == "00"       # 지정가
+
+    @pytest.mark.asyncio
+    async def test_limit_order_ord_dvsn_is_00(self, broker: KISBroker) -> None:
+        """send_order with price>0 must use ORD_DVSN='00' (지정가)."""
+        mock_hash = AsyncMock()
+        mock_hash.status = 200
+        mock_hash.json = AsyncMock(return_value={"HASH": "h"})
+        mock_hash.__aenter__ = AsyncMock(return_value=mock_hash)
+        mock_hash.__aexit__ = AsyncMock(return_value=False)
+
+        mock_order = AsyncMock()
+        mock_order.status = 200
+        mock_order.json = AsyncMock(return_value={"rt_cd": "0"})
+        mock_order.__aenter__ = AsyncMock(return_value=mock_order)
+        mock_order.__aexit__ = AsyncMock(return_value=False)
+
+        with patch(
+            "aiohttp.ClientSession.post", side_effect=[mock_hash, mock_order]
+        ) as mock_post:
+            await broker.send_order("005930", "BUY", 1, price=50000)
+
+        order_call = mock_post.call_args_list[1]
+        body = order_call[1].get("json", {})
+        assert body["ORD_DVSN"] == "00"
+
+    @pytest.mark.asyncio
+    async def test_market_order_ord_dvsn_is_01(self, broker: KISBroker) -> None:
+        """send_order with price=0 must use ORD_DVSN='01' (시장가)."""
+        mock_hash = AsyncMock()
+        mock_hash.status = 200
+        mock_hash.json = AsyncMock(return_value={"HASH": "h"})
+        mock_hash.__aenter__ = AsyncMock(return_value=mock_hash)
+        mock_hash.__aexit__ = AsyncMock(return_value=False)
+
+        mock_order = AsyncMock()
+        mock_order.status = 200
+        mock_order.json = AsyncMock(return_value={"rt_cd": "0"})
+        mock_order.__aenter__ = AsyncMock(return_value=mock_order)
+        mock_order.__aexit__ = AsyncMock(return_value=False)
+
+        with patch(
+            "aiohttp.ClientSession.post", side_effect=[mock_hash, mock_order]
+        ) as mock_post:
+            await broker.send_order("005930", "SELL", 1, price=0)
+
+        order_call = mock_post.call_args_list[1]
+        body = order_call[1].get("json", {})
+        assert body["ORD_DVSN"] == "01"
+        assert body["ORD_UNPR"] == "0"

tests/test_main.py

@@ -111,15 +111,7 @@ class TestTradingCycleTelegramIntegration:
     def mock_broker(self) -> MagicMock:
         """Create mock broker."""
         broker = MagicMock()
-        broker.get_orderbook = AsyncMock(
-            return_value={
-                "output1": {
-                    "stck_prpr": "50000",
-                    "frgn_ntby_qty": "100",
-                    "prdy_ctrt": "1.23",
-                }
-            }
-        )
+        broker.get_current_price = AsyncMock(return_value=(50000.0, 1.23, 100.0))
         broker.get_balance = AsyncMock(
             return_value={
                 "output2": [
@@ -823,11 +815,7 @@ class TestScenarioEngineIntegration:
     def mock_broker(self) -> MagicMock:
         """Create mock broker with standard domestic data."""
         broker = MagicMock()
-        broker.get_orderbook = AsyncMock(
-            return_value={
-                "output1": {"stck_prpr": "50000", "frgn_ntby_qty": "100", "prdy_ctrt": "2.50"}
-            }
-        )
+        broker.get_current_price = AsyncMock(return_value=(50000.0, 2.50, 100.0))
         broker.get_balance = AsyncMock(
             return_value={
                 "output2": [
@@ -1249,9 +1237,7 @@ async def test_sell_updates_original_buy_decision_outcome() -> None:
     )
 
     broker = MagicMock()
-    broker.get_orderbook = AsyncMock(
-        return_value={"output1": {"stck_prpr": "120", "frgn_ntby_qty": "0"}}
-    )
+    broker.get_current_price = AsyncMock(return_value=(120.0, 0.0, 0.0))
     broker.get_balance = AsyncMock(
         return_value={
             "output2": [
@@ -1341,9 +1327,7 @@ async def test_hold_overridden_to_sell_when_stop_loss_triggered() -> None:
     )
 
     broker = MagicMock()
-    broker.get_orderbook = AsyncMock(
-        return_value={"output1": {"stck_prpr": "95", "frgn_ntby_qty": "0", "prdy_ctrt": "-5.0"}}
-    )
+    broker.get_current_price = AsyncMock(return_value=(95.0, -5.0, 0.0))
     broker.get_balance = AsyncMock(
         return_value={
             "output2": [