Merge main into feature/issue-49-valueerror-empty-string

Resolved conflict in src/main.py by using safe_float() from main
instead of float(...or '0') pattern.

Changes:
- src/main.py: Use safe_float() for consistent empty string handling
- All 16 tests pass including test_overseas_price_empty_string

src/analysis/scanner.py

@@ -83,8 +83,8 @@ class MarketScanner:
                 # Convert to orderbook-like structure
                 orderbook = {
                     "output1": {
-                        "stck_prpr": price_data.get("output", {}).get("last", "0"),
+                        "stck_prpr": price_data.get("output", {}).get("last", "0") or "0",
-                        "acml_vol": price_data.get("output", {}).get("tvol", "0"),
+                        "acml_vol": price_data.get("output", {}).get("tvol", "0") or "0",
                     }
                 }
 

src/main.py

@@ -33,6 +33,35 @@ from src.notifications.telegram_client import TelegramClient
 
 logger = logging.getLogger(__name__)
 
+
+def safe_float(value: str | float | None, default: float = 0.0) -> float:
+    """Convert to float, handling empty strings and None.
+
+    Args:
+        value: Value to convert (string, float, or None)
+        default: Default value if conversion fails
+
+    Returns:
+        Converted float or default value
+
+    Examples:
+        >>> safe_float("123.45")
+        123.45
+        >>> safe_float("")
+        0.0
+        >>> safe_float(None)
+        0.0
+        >>> safe_float("invalid", 99.0)
+        99.0
+    """
+    if value is None or value == "":
+        return default
+    try:
+        return float(value)
+    except (ValueError, TypeError):
+        return default
+
+
 # Target stock codes to monitor per market
 WATCHLISTS = {
     "KR": ["005930", "000660", "035420"],  # Samsung, SK Hynix, NAVER
@@ -77,16 +106,16 @@ async def trading_cycle(
         balance_data = await broker.get_balance()
 
         output2 = balance_data.get("output2", [{}])
-        total_eval = float(output2[0].get("tot_evlu_amt", "0")) if output2 else 0
+        total_eval = safe_float(output2[0].get("tot_evlu_amt", "0")) if output2 else 0
-        total_cash = float(
+        total_cash = safe_float(
             balance_data.get("output2", [{}])[0].get("dnca_tot_amt", "0")
             if output2
             else "0"
         )
-        purchase_total = float(output2[0].get("pchs_amt_smtl_amt", "0")) if output2 else 0
+        purchase_total = safe_float(output2[0].get("pchs_amt_smtl_amt", "0")) if output2 else 0
 
-        current_price = float(orderbook.get("output1", {}).get("stck_prpr", "0"))
+        current_price = safe_float(orderbook.get("output1", {}).get("stck_prpr", "0"))
-        foreigner_net = float(orderbook.get("output1", {}).get("frgn_ntby_qty", "0"))
+        foreigner_net = safe_float(orderbook.get("output1", {}).get("frgn_ntby_qty", "0"))
     else:
         # Overseas market
         price_data = await overseas_broker.get_overseas_price(
@@ -103,11 +132,11 @@ async def trading_cycle(
         else:
             balance_info = {}
 
-        total_eval = float(balance_info.get("frcr_evlu_tota", "0") or "0")
+        total_eval = safe_float(balance_info.get("frcr_evlu_tota", "0") or "0")
-        total_cash = float(balance_info.get("frcr_dncl_amt_2", "0") or "0")
+        total_cash = safe_float(balance_info.get("frcr_dncl_amt_2", "0") or "0")
-        purchase_total = float(balance_info.get("frcr_buy_amt_smtl", "0") or "0")
+        purchase_total = safe_float(balance_info.get("frcr_buy_amt_smtl", "0") or "0")
 
-        current_price = float(price_data.get("output", {}).get("last", "0"))
+        current_price = safe_float(price_data.get("output", {}).get("last", "0"))
         foreigner_net = 0.0  # Not available for overseas
 
     # Calculate daily P&L %

tests/test_main.py

@@ -6,7 +6,43 @@ from unittest.mock import AsyncMock, MagicMock, patch
 import pytest
 
 from src.core.risk_manager import CircuitBreakerTripped, FatFingerRejected
-from src.main import trading_cycle
+from src.main import safe_float, trading_cycle
+
+
+class TestSafeFloat:
+    """Test safe_float() helper function."""
+
+    def test_converts_valid_string(self):
+        """Test conversion of valid numeric string."""
+        assert safe_float("123.45") == 123.45
+        assert safe_float("0") == 0.0
+        assert safe_float("-99.9") == -99.9
+
+    def test_handles_empty_string(self):
+        """Test empty string returns default."""
+        assert safe_float("") == 0.0
+        assert safe_float("", 99.0) == 99.0
+
+    def test_handles_none(self):
+        """Test None returns default."""
+        assert safe_float(None) == 0.0
+        assert safe_float(None, 42.0) == 42.0
+
+    def test_handles_invalid_string(self):
+        """Test invalid string returns default."""
+        assert safe_float("invalid") == 0.0
+        assert safe_float("not_a_number", 100.0) == 100.0
+        assert safe_float("12.34.56") == 0.0
+
+    def test_handles_float_input(self):
+        """Test float input passes through."""
+        assert safe_float(123.45) == 123.45
+        assert safe_float(0.0) == 0.0
+
+    def test_custom_default(self):
+        """Test custom default value."""
+        assert safe_float("", -1.0) == -1.0
+        assert safe_float(None, 999.0) == 999.0
 
 
 class TestTradingCycleTelegramIntegration:
@@ -394,6 +430,26 @@ class TestOverseasBalanceParsing:
         broker.get_overseas_balance = AsyncMock(return_value={"output2": []})
         return broker
 
+    @pytest.fixture
+    def mock_overseas_broker_with_empty_price(self) -> MagicMock:
+        """Create mock overseas broker returning empty string for price."""
+        broker = MagicMock()
+        broker.get_overseas_price = AsyncMock(
+            return_value={"output": {"last": ""}}  # Empty string
+        )
+        broker.get_overseas_balance = AsyncMock(
+            return_value={
+                "output2": [
+                    {
+                        "frcr_evlu_tota": "10000.00",
+                        "frcr_dncl_amt_2": "5000.00",
+                        "frcr_buy_amt_smtl": "4500.00",
+                    }
+                ]
+            }
+        )
+        return broker
+
     @pytest.fixture
     def mock_domestic_broker(self) -> MagicMock:
         """Create minimal mock domestic broker."""
@@ -559,3 +615,37 @@ class TestOverseasBalanceParsing:
 
         # Verify balance API was called
         mock_overseas_broker_with_empty.get_overseas_balance.assert_called_once()
+
+    @pytest.mark.asyncio
+    async def test_overseas_price_empty_string(
+        self,
+        mock_domestic_broker: MagicMock,
+        mock_overseas_broker_with_empty_price: MagicMock,
+        mock_brain_hold: MagicMock,
+        mock_risk: MagicMock,
+        mock_db: MagicMock,
+        mock_decision_logger: MagicMock,
+        mock_context_store: MagicMock,
+        mock_criticality_assessor: MagicMock,
+        mock_telegram: MagicMock,
+        mock_overseas_market: MagicMock,
+    ) -> None:
+        """Test overseas price parsing with empty string (issue #49)."""
+        with patch("src.main.log_trade"):
+            # Should not raise ValueError, should default to 0.0
+            await trading_cycle(
+                broker=mock_domestic_broker,
+                overseas_broker=mock_overseas_broker_with_empty_price,
+                brain=mock_brain_hold,
+                risk=mock_risk,
+                db_conn=mock_db,
+                decision_logger=mock_decision_logger,
+                context_store=mock_context_store,
+                criticality_assessor=mock_criticality_assessor,
+                telegram=mock_telegram,
+                market=mock_overseas_market,
+                stock_code="AAPL",
+            )
+
+        # Verify price API was called
+        mock_overseas_broker_with_empty_price.get_overseas_price.assert_called_once()

tests/test_volatility.py

@@ -338,6 +338,28 @@ class TestMarketScanner:
         assert metrics.stock_code == "AAPL"
         assert metrics.current_price == 150.50
 
+    @pytest.mark.asyncio
+    async def test_scan_stock_overseas_empty_price(
+        self,
+        scanner: MarketScanner,
+        mock_overseas_broker: OverseasBroker,
+        context_store: ContextStore,
+    ) -> None:
+        """Test scanning overseas stock with empty price string (issue #49)."""
+        mock_overseas_broker.get_overseas_price.return_value = {
+            "output": {
+                "last": "",  # Empty string
+                "tvol": "",  # Empty string
+            }
+        }
+
+        market = MARKETS["US_NASDAQ"]
+        metrics = await scanner.scan_stock("AAPL", market)
+
+        assert metrics is not None
+        assert metrics.stock_code == "AAPL"
+        assert metrics.current_price == 0.0  # Should default to 0.0
+
     @pytest.mark.asyncio
     async def test_scan_stock_error_handling(
         self,