fix: align cooldown test with wait-and-retry behavior + boost overseas coverage

- test_token_refresh_cooldown: updated to match the wait-then-retry
  behavior introduced in aeed881 (was expecting fail-fast ConnectionError)
- Added 22 tests for OverseasBroker: get_overseas_price, get_overseas_balance,
  send_overseas_order, _get_currency_code, _extract_ranking_rows
- src/broker/overseas.py coverage: 52% → 100%
- All 594 tests pass

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

docs/requirements-log.md

@@ -165,3 +165,22 @@
 **효과:**
 - 국내/해외 스캐너 기준이 변동성 중심으로 일관화
 - 고변동 구간에서 자동 익스포저 축소, 저변동 구간에서 과소진입 완화
+
+## 2026-02-18
+
+### KIS 해외 랭킹 API 404 에러 수정
+
+**배경:**
+- KIS 해외주식 랭킹 API(`fetch_overseas_rankings`)가 모든 거래소에서 HTTP 404를 반환
+- Smart Scanner가 해외 시장 후보 종목을 찾지 못해 거래가 전혀 실행되지 않음
+
+**근본 원인:**
+- TR_ID, API 경로, 거래소 코드가 모두 KIS 공식 문서와 불일치
+
+**구현 결과:**
+- `src/config.py`: TR_ID/Path 기본값을 KIS 공식 스펙으로 수정
+- `src/broker/overseas.py`: 랭킹 API 전용 거래소 코드 매핑 추가 (NASD→NAS, NYSE→NYS, AMEX→AMS), 올바른 API 파라미터 사용
+- `tests/test_overseas_broker.py`: 19개 단위 테스트 추가
+
+**효과:**
+- 해외 시장 랭킹 스캔이 정상 동작하여 Smart Scanner가 후보 종목 탐지 가능

src/broker/overseas.py

@@ -12,6 +12,20 @@ from src.broker.kis_api import KISBroker
 logger = logging.getLogger(__name__)
 
 
+# Ranking API uses different exchange codes than order/quote APIs.
+_RANKING_EXCHANGE_MAP: dict[str, str] = {
+    "NASD": "NAS",
+    "NYSE": "NYS",
+    "AMEX": "AMS",
+    "SEHK": "HKS",
+    "SHAA": "SHS",
+    "SZAA": "SZS",
+    "HSX": "HSX",
+    "HNX": "HNX",
+    "TSE": "TSE",
+}
+
+
 class OverseasBroker:
     """KIS Overseas Stock API wrapper that reuses KISBroker infrastructure."""
 
@@ -70,7 +84,7 @@ class OverseasBroker:
         ranking_type: str = "fluctuation",
         limit: int = 30,
     ) -> list[dict[str, Any]]:
-        """Fetch overseas rankings (price change or volume amount).
+        """Fetch overseas rankings (price change or volume surge).
 
         Ranking API specs may differ by account/product. Endpoint paths and
         TR_IDs are configurable via settings and can be overridden in .env.
@@ -81,66 +95,63 @@ class OverseasBroker:
         await self._broker._rate_limiter.acquire()
         session = self._broker._get_session()
 
+        ranking_excd = _RANKING_EXCHANGE_MAP.get(exchange_code, exchange_code)
+
         if ranking_type == "volume":
-            configured_tr_id = self._broker._settings.OVERSEAS_RANKING_VOLUME_TR_ID
-            configured_path = self._broker._settings.OVERSEAS_RANKING_VOLUME_PATH
-            default_tr_id = "HHDFS76200200"
-            default_path = "/uapi/overseas-price/v1/quotations/inquire-volume-rank"
+            tr_id = self._broker._settings.OVERSEAS_RANKING_VOLUME_TR_ID
+            path = self._broker._settings.OVERSEAS_RANKING_VOLUME_PATH
+            params: dict[str, str] = {
+                "AUTH": "",
+                "EXCD": ranking_excd,
+                "MIXN": "0",
+                "VOL_RANG": "0",
+            }
         else:
-            configured_tr_id = self._broker._settings.OVERSEAS_RANKING_FLUCT_TR_ID
-            configured_path = self._broker._settings.OVERSEAS_RANKING_FLUCT_PATH
-            default_tr_id = "HHDFS76200100"
-            default_path = "/uapi/overseas-price/v1/quotations/inquire-updown-rank"
+            tr_id = self._broker._settings.OVERSEAS_RANKING_FLUCT_TR_ID
+            path = self._broker._settings.OVERSEAS_RANKING_FLUCT_PATH
+            params = {
+                "AUTH": "",
+                "EXCD": ranking_excd,
+                "NDAY": "0",
+                "GUBN": "1",
+                "VOL_RANG": "0",
+            }
 
-        endpoint_specs: list[tuple[str, str]] = [(configured_tr_id, configured_path)]
-        if (configured_tr_id, configured_path) != (default_tr_id, default_path):
-            endpoint_specs.append((default_tr_id, default_path))
-
-        # Try common param variants used by KIS overseas quotation APIs.
-        param_variants = [
-            {"AUTH": "", "EXCD": exchange_code, "NREC": str(max(limit, 30))},
-            {"AUTH": "", "OVRS_EXCG_CD": exchange_code, "NREC": str(max(limit, 30))},
-            {"AUTH": "", "EXCD": exchange_code},
-            {"AUTH": "", "OVRS_EXCG_CD": exchange_code},
-        ]
-
-        last_error: str | None = None
-        saw_http_404 = False
-        for tr_id, path in endpoint_specs:
         headers = await self._broker._auth_headers(tr_id)
         url = f"{self._broker._base_url}{path}"
-            for params in param_variants:
+
         try:
             async with session.get(url, headers=headers, params=params) as resp:
-                        text = await resp.text()
                 if resp.status != 200:
-                            last_error = f"HTTP {resp.status}: {text}"
+                    text = await resp.text()
                     if resp.status == 404:
-                                saw_http_404 = True
-                            continue
+                        logger.warning(
+                            "Overseas ranking endpoint unavailable (404) for %s/%s; "
+                            "using symbol fallback scan",
+                            exchange_code,
+                            ranking_type,
+                        )
+                        return []
+                    raise ConnectionError(
+                        f"fetch_overseas_rankings failed ({resp.status}): {text}"
+                    )
 
                 data = await resp.json()
                 rows = self._extract_ranking_rows(data)
                 if rows:
                     return rows[:limit]
 
-                        # keep trying another param variant if response has no usable rows
-                        last_error = f"empty output (keys={list(data.keys())})"
-                except (TimeoutError, aiohttp.ClientError) as exc:
-                    last_error = str(exc)
-                    continue
-
-        if saw_http_404:
-            logger.warning(
-                "Overseas ranking endpoint unavailable (404) for %s/%s; using symbol fallback scan",
+                logger.debug(
+                    "Overseas ranking returned empty for %s/%s (keys=%s)",
                     exchange_code,
                     ranking_type,
+                    list(data.keys()),
                 )
                 return []
-
+        except (TimeoutError, aiohttp.ClientError) as exc:
             raise ConnectionError(
-            f"fetch_overseas_rankings failed for {exchange_code}/{ranking_type}: {last_error}"
-        )
+                f"Network error fetching overseas rankings: {exc}"
+            ) from exc
 
     async def get_overseas_balance(self, exchange_code: str) -> dict[str, Any]:
         """

src/config.py

@@ -91,13 +91,13 @@ class Settings(BaseSettings):
     # Overseas ranking API (KIS endpoint/TR_ID may vary by account/product)
     # Override these from .env if your account uses different specs.
     OVERSEAS_RANKING_ENABLED: bool = True
-    OVERSEAS_RANKING_FLUCT_TR_ID: str = "HHDFS76200100"
-    OVERSEAS_RANKING_VOLUME_TR_ID: str = "HHDFS76200200"
+    OVERSEAS_RANKING_FLUCT_TR_ID: str = "HHDFS76290000"
+    OVERSEAS_RANKING_VOLUME_TR_ID: str = "HHDFS76270000"
     OVERSEAS_RANKING_FLUCT_PATH: str = (
-        "/uapi/overseas-price/v1/quotations/inquire-updown-rank"
+        "/uapi/overseas-stock/v1/ranking/updown-rate"
     )
     OVERSEAS_RANKING_VOLUME_PATH: str = (
-        "/uapi/overseas-price/v1/quotations/inquire-volume-rank"
+        "/uapi/overseas-stock/v1/ranking/volume-surge"
     )
 
     # Dashboard (optional)

tests/test_broker.py

@@ -90,12 +90,12 @@ class TestTokenManagement:
         await broker.close()
 
     @pytest.mark.asyncio
-    async def test_token_refresh_cooldown_prevents_rapid_retries(self, settings):
-        """Token refresh should enforce cooldown after failure (issue #54)."""
+    async def test_token_refresh_cooldown_waits_then_retries(self, settings):
+        """Token refresh should wait out cooldown then retry (issue #54)."""
         broker = KISBroker(settings)
-        broker._refresh_cooldown = 2.0  # Short cooldown for testing
+        broker._refresh_cooldown = 0.1  # Short cooldown for testing
 
-        # First refresh attempt fails with 403 (EGW00133)
+        # All attempts fail with 403 (EGW00133)
         mock_resp_403 = AsyncMock()
         mock_resp_403.status = 403
         mock_resp_403.text = AsyncMock(
@@ -109,8 +109,8 @@ class TestTokenManagement:
             with pytest.raises(ConnectionError, match="Token refresh failed"):
                 await broker._ensure_token()
 
-            # Second attempt within cooldown should fail with cooldown error
-            with pytest.raises(ConnectionError, match="Token refresh on cooldown"):
+            # Second attempt within cooldown should wait then retry (and still get 403)
+            with pytest.raises(ConnectionError, match="Token refresh failed"):
                 await broker._ensure_token()
 
         await broker.close()

tests/test_overseas_broker.py

@@ -0,0 +1,521 @@
+"""Tests for OverseasBroker — rankings, price, balance, order, and helpers."""
+
+from __future__ import annotations
+
+from unittest.mock import AsyncMock, MagicMock
+
+import aiohttp
+import pytest
+
+from src.broker.kis_api import KISBroker
+from src.broker.overseas import OverseasBroker, _RANKING_EXCHANGE_MAP
+from src.config import Settings
+
+
+def _make_async_cm(mock_resp: AsyncMock) -> MagicMock:
+    """Create an async context manager that returns mock_resp on __aenter__."""
+    cm = MagicMock()
+    cm.__aenter__ = AsyncMock(return_value=mock_resp)
+    cm.__aexit__ = AsyncMock(return_value=False)
+    return cm
+
+
+@pytest.fixture
+def mock_settings() -> Settings:
+    """Provide mock settings with correct default TR_IDs/paths."""
+    return Settings(
+        KIS_APP_KEY="test_key",
+        KIS_APP_SECRET="test_secret",
+        KIS_ACCOUNT_NO="12345678-01",
+        GEMINI_API_KEY="test_gemini_key",
+    )
+
+
+@pytest.fixture
+def mock_broker(mock_settings: Settings) -> KISBroker:
+    """Provide a mock KIS broker."""
+    broker = KISBroker(mock_settings)
+    broker.get_orderbook = AsyncMock()  # type: ignore[method-assign]
+    return broker
+
+
+@pytest.fixture
+def overseas_broker(mock_broker: KISBroker) -> OverseasBroker:
+    """Provide an OverseasBroker wrapping a mock KISBroker."""
+    return OverseasBroker(mock_broker)
+
+
+def _setup_broker_mocks(overseas_broker: OverseasBroker, mock_session: MagicMock) -> None:
+    """Wire up common broker mocks."""
+    overseas_broker._broker._rate_limiter.acquire = AsyncMock()
+    overseas_broker._broker._get_session = MagicMock(return_value=mock_session)
+    overseas_broker._broker._auth_headers = AsyncMock(return_value={})
+
+
+class TestRankingExchangeMap:
+    """Test exchange code mapping for ranking API."""
+
+    def test_nasd_maps_to_nas(self) -> None:
+        assert _RANKING_EXCHANGE_MAP["NASD"] == "NAS"
+
+    def test_nyse_maps_to_nys(self) -> None:
+        assert _RANKING_EXCHANGE_MAP["NYSE"] == "NYS"
+
+    def test_amex_maps_to_ams(self) -> None:
+        assert _RANKING_EXCHANGE_MAP["AMEX"] == "AMS"
+
+    def test_sehk_maps_to_hks(self) -> None:
+        assert _RANKING_EXCHANGE_MAP["SEHK"] == "HKS"
+
+    def test_unmapped_exchange_passes_through(self) -> None:
+        assert _RANKING_EXCHANGE_MAP.get("UNKNOWN", "UNKNOWN") == "UNKNOWN"
+
+    def test_tse_unchanged(self) -> None:
+        assert _RANKING_EXCHANGE_MAP["TSE"] == "TSE"
+
+
+class TestConfigDefaults:
+    """Test that config defaults match KIS official API specs."""
+
+    def test_fluct_tr_id(self, mock_settings: Settings) -> None:
+        assert mock_settings.OVERSEAS_RANKING_FLUCT_TR_ID == "HHDFS76290000"
+
+    def test_volume_tr_id(self, mock_settings: Settings) -> None:
+        assert mock_settings.OVERSEAS_RANKING_VOLUME_TR_ID == "HHDFS76270000"
+
+    def test_fluct_path(self, mock_settings: Settings) -> None:
+        assert mock_settings.OVERSEAS_RANKING_FLUCT_PATH == "/uapi/overseas-stock/v1/ranking/updown-rate"
+
+    def test_volume_path(self, mock_settings: Settings) -> None:
+        assert mock_settings.OVERSEAS_RANKING_VOLUME_PATH == "/uapi/overseas-stock/v1/ranking/volume-surge"
+
+
+class TestFetchOverseasRankings:
+    """Test fetch_overseas_rankings method."""
+
+    @pytest.mark.asyncio
+    async def test_fluctuation_uses_correct_params(
+        self, overseas_broker: OverseasBroker
+    ) -> None:
+        """Fluctuation ranking should use HHDFS76290000, updown-rate path, and correct params."""
+        mock_resp = AsyncMock()
+        mock_resp.status = 200
+        mock_resp.json = AsyncMock(
+            return_value={"output": [{"symb": "AAPL", "name": "Apple"}]}
+        )
+
+        mock_session = MagicMock()
+        mock_session.get = MagicMock(return_value=_make_async_cm(mock_resp))
+
+        _setup_broker_mocks(overseas_broker, mock_session)
+        overseas_broker._broker._auth_headers = AsyncMock(
+            return_value={"authorization": "Bearer test"}
+        )
+
+        result = await overseas_broker.fetch_overseas_rankings("NASD", "fluctuation")
+
+        assert len(result) == 1
+        assert result[0]["symb"] == "AAPL"
+
+        call_args = mock_session.get.call_args
+        url = call_args[0][0]
+        params = call_args[1]["params"]
+
+        assert "/uapi/overseas-stock/v1/ranking/updown-rate" in url
+        assert params["EXCD"] == "NAS"
+        assert params["NDAY"] == "0"
+        assert params["GUBN"] == "1"
+        assert params["VOL_RANG"] == "0"
+
+        overseas_broker._broker._auth_headers.assert_called_with("HHDFS76290000")
+
+    @pytest.mark.asyncio
+    async def test_volume_uses_correct_params(
+        self, overseas_broker: OverseasBroker
+    ) -> None:
+        """Volume ranking should use HHDFS76270000, volume-surge path, and correct params."""
+        mock_resp = AsyncMock()
+        mock_resp.status = 200
+        mock_resp.json = AsyncMock(
+            return_value={"output": [{"symb": "TSLA", "name": "Tesla"}]}
+        )
+
+        mock_session = MagicMock()
+        mock_session.get = MagicMock(return_value=_make_async_cm(mock_resp))
+
+        _setup_broker_mocks(overseas_broker, mock_session)
+        overseas_broker._broker._auth_headers = AsyncMock(
+            return_value={"authorization": "Bearer test"}
+        )
+
+        result = await overseas_broker.fetch_overseas_rankings("NYSE", "volume")
+
+        assert len(result) == 1
+
+        call_args = mock_session.get.call_args
+        url = call_args[0][0]
+        params = call_args[1]["params"]
+
+        assert "/uapi/overseas-stock/v1/ranking/volume-surge" in url
+        assert params["EXCD"] == "NYS"
+        assert params["MIXN"] == "0"
+        assert params["VOL_RANG"] == "0"
+        assert "NDAY" not in params
+        assert "GUBN" not in params
+
+        overseas_broker._broker._auth_headers.assert_called_with("HHDFS76270000")
+
+    @pytest.mark.asyncio
+    async def test_404_returns_empty_list(
+        self, overseas_broker: OverseasBroker
+    ) -> None:
+        """HTTP 404 should return empty list (fallback) instead of raising."""
+        mock_resp = AsyncMock()
+        mock_resp.status = 404
+        mock_resp.text = AsyncMock(return_value="Not Found")
+
+        mock_session = MagicMock()
+        mock_session.get = MagicMock(return_value=_make_async_cm(mock_resp))
+
+        _setup_broker_mocks(overseas_broker, mock_session)
+
+        result = await overseas_broker.fetch_overseas_rankings("AMEX", "fluctuation")
+        assert result == []
+
+    @pytest.mark.asyncio
+    async def test_non_404_error_raises(
+        self, overseas_broker: OverseasBroker
+    ) -> None:
+        """Non-404 HTTP errors should raise ConnectionError."""
+        mock_resp = AsyncMock()
+        mock_resp.status = 500
+        mock_resp.text = AsyncMock(return_value="Internal Server Error")
+
+        mock_session = MagicMock()
+        mock_session.get = MagicMock(return_value=_make_async_cm(mock_resp))
+
+        _setup_broker_mocks(overseas_broker, mock_session)
+
+        with pytest.raises(ConnectionError, match="500"):
+            await overseas_broker.fetch_overseas_rankings("NASD")
+
+    @pytest.mark.asyncio
+    async def test_empty_response_returns_empty(
+        self, overseas_broker: OverseasBroker
+    ) -> None:
+        """Empty output in response should return empty list."""
+        mock_resp = AsyncMock()
+        mock_resp.status = 200
+        mock_resp.json = AsyncMock(return_value={"output": []})
+
+        mock_session = MagicMock()
+        mock_session.get = MagicMock(return_value=_make_async_cm(mock_resp))
+
+        _setup_broker_mocks(overseas_broker, mock_session)
+
+        result = await overseas_broker.fetch_overseas_rankings("NASD")
+        assert result == []
+
+    @pytest.mark.asyncio
+    async def test_ranking_disabled_returns_empty(
+        self, overseas_broker: OverseasBroker
+    ) -> None:
+        """When OVERSEAS_RANKING_ENABLED=False, should return empty immediately."""
+        overseas_broker._broker._settings.OVERSEAS_RANKING_ENABLED = False
+        result = await overseas_broker.fetch_overseas_rankings("NASD")
+        assert result == []
+
+    @pytest.mark.asyncio
+    async def test_limit_truncates_results(
+        self, overseas_broker: OverseasBroker
+    ) -> None:
+        """Results should be truncated to the specified limit."""
+        rows = [{"symb": f"SYM{i}"} for i in range(20)]
+        mock_resp = AsyncMock()
+        mock_resp.status = 200
+        mock_resp.json = AsyncMock(return_value={"output": rows})
+
+        mock_session = MagicMock()
+        mock_session.get = MagicMock(return_value=_make_async_cm(mock_resp))
+
+        _setup_broker_mocks(overseas_broker, mock_session)
+
+        result = await overseas_broker.fetch_overseas_rankings("NASD", limit=5)
+        assert len(result) == 5
+
+    @pytest.mark.asyncio
+    async def test_network_error_raises(
+        self, overseas_broker: OverseasBroker
+    ) -> None:
+        """Network errors should raise ConnectionError."""
+        cm = MagicMock()
+        cm.__aenter__ = AsyncMock(side_effect=aiohttp.ClientError("timeout"))
+        cm.__aexit__ = AsyncMock(return_value=False)
+
+        mock_session = MagicMock()
+        mock_session.get = MagicMock(return_value=cm)
+
+        _setup_broker_mocks(overseas_broker, mock_session)
+
+        with pytest.raises(ConnectionError, match="Network error"):
+            await overseas_broker.fetch_overseas_rankings("NASD")
+
+    @pytest.mark.asyncio
+    async def test_exchange_code_mapping_applied(
+        self, overseas_broker: OverseasBroker
+    ) -> None:
+        """All major exchanges should use mapped codes in API params."""
+        for original, mapped in [("NASD", "NAS"), ("NYSE", "NYS"), ("AMEX", "AMS")]:
+            mock_resp = AsyncMock()
+            mock_resp.status = 200
+            mock_resp.json = AsyncMock(return_value={"output": [{"symb": "X"}]})
+
+            mock_session = MagicMock()
+            mock_session.get = MagicMock(return_value=_make_async_cm(mock_resp))
+
+            _setup_broker_mocks(overseas_broker, mock_session)
+
+            await overseas_broker.fetch_overseas_rankings(original)
+
+            call_params = mock_session.get.call_args[1]["params"]
+            assert call_params["EXCD"] == mapped, f"{original} should map to {mapped}"
+
+
+class TestGetOverseasPrice:
+    """Test get_overseas_price method."""
+
+    @pytest.mark.asyncio
+    async def test_success(self, overseas_broker: OverseasBroker) -> None:
+        """Successful price fetch returns JSON data."""
+        mock_resp = AsyncMock()
+        mock_resp.status = 200
+        mock_resp.json = AsyncMock(return_value={"output": {"last": "150.00"}})
+
+        mock_session = MagicMock()
+        mock_session.get = MagicMock(return_value=_make_async_cm(mock_resp))
+
+        _setup_broker_mocks(overseas_broker, mock_session)
+        overseas_broker._broker._auth_headers = AsyncMock(return_value={"authorization": "Bearer t"})
+
+        result = await overseas_broker.get_overseas_price("NASD", "AAPL")
+        assert result["output"]["last"] == "150.00"
+
+        call_args = mock_session.get.call_args
+        params = call_args[1]["params"]
+        assert params["EXCD"] == "NASD"
+        assert params["SYMB"] == "AAPL"
+
+    @pytest.mark.asyncio
+    async def test_http_error_raises(self, overseas_broker: OverseasBroker) -> None:
+        """Non-200 response should raise ConnectionError."""
+        mock_resp = AsyncMock()
+        mock_resp.status = 400
+        mock_resp.text = AsyncMock(return_value="Bad Request")
+
+        mock_session = MagicMock()
+        mock_session.get = MagicMock(return_value=_make_async_cm(mock_resp))
+
+        _setup_broker_mocks(overseas_broker, mock_session)
+
+        with pytest.raises(ConnectionError, match="get_overseas_price failed"):
+            await overseas_broker.get_overseas_price("NASD", "AAPL")
+
+    @pytest.mark.asyncio
+    async def test_network_error_raises(self, overseas_broker: OverseasBroker) -> None:
+        """Network error should raise ConnectionError."""
+        cm = MagicMock()
+        cm.__aenter__ = AsyncMock(side_effect=aiohttp.ClientError("conn refused"))
+        cm.__aexit__ = AsyncMock(return_value=False)
+
+        mock_session = MagicMock()
+        mock_session.get = MagicMock(return_value=cm)
+
+        _setup_broker_mocks(overseas_broker, mock_session)
+
+        with pytest.raises(ConnectionError, match="Network error"):
+            await overseas_broker.get_overseas_price("NASD", "AAPL")
+
+
+class TestGetOverseasBalance:
+    """Test get_overseas_balance method."""
+
+    @pytest.mark.asyncio
+    async def test_success(self, overseas_broker: OverseasBroker) -> None:
+        """Successful balance fetch returns JSON data."""
+        mock_resp = AsyncMock()
+        mock_resp.status = 200
+        mock_resp.json = AsyncMock(return_value={"output1": [{"pdno": "AAPL"}]})
+
+        mock_session = MagicMock()
+        mock_session.get = MagicMock(return_value=_make_async_cm(mock_resp))
+
+        _setup_broker_mocks(overseas_broker, mock_session)
+
+        result = await overseas_broker.get_overseas_balance("NASD")
+        assert result["output1"][0]["pdno"] == "AAPL"
+
+    @pytest.mark.asyncio
+    async def test_http_error_raises(self, overseas_broker: OverseasBroker) -> None:
+        """Non-200 should raise ConnectionError."""
+        mock_resp = AsyncMock()
+        mock_resp.status = 500
+        mock_resp.text = AsyncMock(return_value="Server Error")
+
+        mock_session = MagicMock()
+        mock_session.get = MagicMock(return_value=_make_async_cm(mock_resp))
+
+        _setup_broker_mocks(overseas_broker, mock_session)
+
+        with pytest.raises(ConnectionError, match="get_overseas_balance failed"):
+            await overseas_broker.get_overseas_balance("NASD")
+
+    @pytest.mark.asyncio
+    async def test_network_error_raises(self, overseas_broker: OverseasBroker) -> None:
+        """Network error should raise ConnectionError."""
+        cm = MagicMock()
+        cm.__aenter__ = AsyncMock(side_effect=TimeoutError("timeout"))
+        cm.__aexit__ = AsyncMock(return_value=False)
+
+        mock_session = MagicMock()
+        mock_session.get = MagicMock(return_value=cm)
+
+        _setup_broker_mocks(overseas_broker, mock_session)
+
+        with pytest.raises(ConnectionError, match="Network error"):
+            await overseas_broker.get_overseas_balance("NYSE")
+
+
+class TestSendOverseasOrder:
+    """Test send_overseas_order method."""
+
+    @pytest.mark.asyncio
+    async def test_buy_market_order(self, overseas_broker: OverseasBroker) -> None:
+        """Market buy order should use VTTT1002U and ORD_DVSN=01."""
+        mock_resp = AsyncMock()
+        mock_resp.status = 200
+        mock_resp.json = AsyncMock(return_value={"rt_cd": "0"})
+
+        mock_session = MagicMock()
+        mock_session.post = MagicMock(return_value=_make_async_cm(mock_resp))
+
+        _setup_broker_mocks(overseas_broker, mock_session)
+        overseas_broker._broker._get_hash_key = AsyncMock(return_value="hashval")
+
+        result = await overseas_broker.send_overseas_order("NASD", "AAPL", "BUY", 10)
+        assert result["rt_cd"] == "0"
+
+        # Verify BUY TR_ID
+        overseas_broker._broker._auth_headers.assert_called_with("VTTT1002U")
+
+        call_args = mock_session.post.call_args
+        body = call_args[1]["json"]
+        assert body["ORD_DVSN"] == "01"  # market order
+        assert body["OVRS_ORD_UNPR"] == "0"
+
+    @pytest.mark.asyncio
+    async def test_sell_limit_order(self, overseas_broker: OverseasBroker) -> None:
+        """Limit sell order should use VTTT1006U and ORD_DVSN=00."""
+        mock_resp = AsyncMock()
+        mock_resp.status = 200
+        mock_resp.json = AsyncMock(return_value={"rt_cd": "0"})
+
+        mock_session = MagicMock()
+        mock_session.post = MagicMock(return_value=_make_async_cm(mock_resp))
+
+        _setup_broker_mocks(overseas_broker, mock_session)
+        overseas_broker._broker._get_hash_key = AsyncMock(return_value="hashval")
+
+        result = await overseas_broker.send_overseas_order("NYSE", "MSFT", "SELL", 5, price=350.0)
+        assert result["rt_cd"] == "0"
+
+        overseas_broker._broker._auth_headers.assert_called_with("VTTT1006U")
+
+        call_args = mock_session.post.call_args
+        body = call_args[1]["json"]
+        assert body["ORD_DVSN"] == "00"  # limit order
+        assert body["OVRS_ORD_UNPR"] == "350.0"
+
+    @pytest.mark.asyncio
+    async def test_order_http_error_raises(self, overseas_broker: OverseasBroker) -> None:
+        """Non-200 should raise ConnectionError."""
+        mock_resp = AsyncMock()
+        mock_resp.status = 400
+        mock_resp.text = AsyncMock(return_value="Bad Request")
+
+        mock_session = MagicMock()
+        mock_session.post = MagicMock(return_value=_make_async_cm(mock_resp))
+
+        _setup_broker_mocks(overseas_broker, mock_session)
+        overseas_broker._broker._get_hash_key = AsyncMock(return_value="hashval")
+
+        with pytest.raises(ConnectionError, match="send_overseas_order failed"):
+            await overseas_broker.send_overseas_order("NASD", "AAPL", "BUY", 1)
+
+    @pytest.mark.asyncio
+    async def test_order_network_error_raises(self, overseas_broker: OverseasBroker) -> None:
+        """Network error should raise ConnectionError."""
+        cm = MagicMock()
+        cm.__aenter__ = AsyncMock(side_effect=aiohttp.ClientError("conn reset"))
+        cm.__aexit__ = AsyncMock(return_value=False)
+
+        mock_session = MagicMock()
+        mock_session.post = MagicMock(return_value=cm)
+
+        _setup_broker_mocks(overseas_broker, mock_session)
+        overseas_broker._broker._get_hash_key = AsyncMock(return_value="hashval")
+
+        with pytest.raises(ConnectionError, match="Network error"):
+            await overseas_broker.send_overseas_order("NASD", "TSLA", "SELL", 2)
+
+
+class TestGetCurrencyCode:
+    """Test _get_currency_code mapping."""
+
+    def test_us_exchanges(self, overseas_broker: OverseasBroker) -> None:
+        assert overseas_broker._get_currency_code("NASD") == "USD"
+        assert overseas_broker._get_currency_code("NYSE") == "USD"
+        assert overseas_broker._get_currency_code("AMEX") == "USD"
+
+    def test_japan(self, overseas_broker: OverseasBroker) -> None:
+        assert overseas_broker._get_currency_code("TSE") == "JPY"
+
+    def test_hong_kong(self, overseas_broker: OverseasBroker) -> None:
+        assert overseas_broker._get_currency_code("SEHK") == "HKD"
+
+    def test_china(self, overseas_broker: OverseasBroker) -> None:
+        assert overseas_broker._get_currency_code("SHAA") == "CNY"
+        assert overseas_broker._get_currency_code("SZAA") == "CNY"
+
+    def test_vietnam(self, overseas_broker: OverseasBroker) -> None:
+        assert overseas_broker._get_currency_code("HNX") == "VND"
+        assert overseas_broker._get_currency_code("HSX") == "VND"
+
+    def test_unknown_defaults_usd(self, overseas_broker: OverseasBroker) -> None:
+        assert overseas_broker._get_currency_code("UNKNOWN") == "USD"
+
+
+class TestExtractRankingRows:
+    """Test _extract_ranking_rows helper."""
+
+    def test_output_key(self, overseas_broker: OverseasBroker) -> None:
+        data = {"output": [{"a": 1}, {"b": 2}]}
+        assert overseas_broker._extract_ranking_rows(data) == [{"a": 1}, {"b": 2}]
+
+    def test_output1_key(self, overseas_broker: OverseasBroker) -> None:
+        data = {"output1": [{"c": 3}]}
+        assert overseas_broker._extract_ranking_rows(data) == [{"c": 3}]
+
+    def test_output2_key(self, overseas_broker: OverseasBroker) -> None:
+        data = {"output2": [{"d": 4}]}
+        assert overseas_broker._extract_ranking_rows(data) == [{"d": 4}]
+
+    def test_no_list_returns_empty(self, overseas_broker: OverseasBroker) -> None:
+        data = {"output": "not a list"}
+        assert overseas_broker._extract_ranking_rows(data) == []
+
+    def test_empty_data(self, overseas_broker: OverseasBroker) -> None:
+        assert overseas_broker._extract_ranking_rows({}) == []
+
+    def test_filters_non_dict_rows(self, overseas_broker: OverseasBroker) -> None:
+        data = {"output": [{"a": 1}, "invalid", {"b": 2}]}
+        assert overseas_broker._extract_ranking_rows(data) == [{"a": 1}, {"b": 2}]