Merge pull request 'feat: DB WAL 모드 적용, .env.example 정리 (#210, #213, #216)' (#220) from feature/issue-210-213-216-db-wal-env-fix into main

Reviewed-on: #220

tests/test_db.py

@@ -1,5 +1,8 @@
 """Tests for database helper functions."""
 
+import tempfile
+import os
+
 from src.db import get_open_position, init_db, log_trade
 
 
@@ -58,3 +61,37 @@ def test_get_open_position_returns_none_when_latest_is_sell() -> None:
 def test_get_open_position_returns_none_when_no_trades() -> None:
     conn = init_db(":memory:")
     assert get_open_position(conn, "AAPL", "US_NASDAQ") is None
+
+
+# ---------------------------------------------------------------------------
+# WAL mode tests (issue #210)
+# ---------------------------------------------------------------------------
+
+
+def test_wal_mode_applied_to_file_db() -> None:
+    """File-based DB must use WAL journal mode for dashboard concurrent reads."""
+    with tempfile.NamedTemporaryFile(suffix=".db", delete=False) as f:
+        db_path = f.name
+    try:
+        conn = init_db(db_path)
+        cursor = conn.execute("PRAGMA journal_mode")
+        mode = cursor.fetchone()[0]
+        assert mode == "wal", f"Expected WAL mode, got {mode}"
+        conn.close()
+    finally:
+        os.unlink(db_path)
+        # Clean up WAL auxiliary files if they exist
+        for ext in ("-wal", "-shm"):
+            path = db_path + ext
+            if os.path.exists(path):
+                os.unlink(path)
+
+
+def test_wal_mode_not_applied_to_memory_db() -> None:
+    """:memory: DB must not apply WAL (SQLite does not support WAL for in-memory)."""
+    conn = init_db(":memory:")
+    cursor = conn.execute("PRAGMA journal_mode")
+    mode = cursor.fetchone()[0]
+    # In-memory DBs default to 'memory' journal mode
+    assert mode != "wal", "WAL should not be set on in-memory database"
+    conn.close()