Improve backtest lazy loading and test automation

tests/conftest.py

@@ -1,13 +1,102 @@
 from __future__ import annotations
 
+import logging
+import os
+import socket
+import sys
+import threading
+import time
+from collections.abc import Generator
 from datetime import datetime
+from pathlib import Path
 
 import pandas as pd
 import pytest
+import uvicorn
 
 from app.models.portfolio import LombardPortfolio
 from app.strategies.base import StrategyConfig
 
+# Suppress NiceGUI banner noise during test server startup.
+logging.getLogger("nicegui").setLevel(logging.WARNING)
+
+
+def find_free_port() -> int:
+    """Find a free port on localhost."""
+    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
+        sock.bind(("", 0))
+        sock.listen(1)
+        return int(sock.getsockname()[1])
+
+
+class ServerManager:
+    """Manage a background uvicorn server for Playwright-style tests."""
+
+    def __init__(self, port: int) -> None:
+        self.port = port
+        self.url = f"http://127.0.0.1:{port}"
+        self._thread: threading.Thread | None = None
+        self._server: uvicorn.Server | None = None
+
+    def start(self) -> None:
+        self._thread = threading.Thread(target=self._run_server, daemon=True)
+        self._thread.start()
+        if not self._wait_for_connection(timeout=30):
+            raise RuntimeError("Server did not start within 30 seconds")
+
+    def _run_server(self) -> None:
+        project_root = str(Path(__file__).resolve().parent.parent)
+        if project_root not in sys.path:
+            sys.path.insert(0, project_root)
+
+        os.environ.setdefault("APP_ENV", "test")
+        os.environ.setdefault("NICEGUI_STORAGE_SECRET", "test-secret-key")
+
+        from app.main import app
+
+        config = uvicorn.Config(
+            app,
+            host="127.0.0.1",
+            port=self.port,
+            log_level="warning",
+            access_log=False,
+        )
+        self._server = uvicorn.Server(config)
+        self._server.run()
+
+    def _wait_for_connection(self, timeout: float = 10.0) -> bool:
+        deadline = time.time() + timeout
+        while time.time() < deadline:
+            try:
+                with socket.create_connection(("127.0.0.1", self.port), timeout=1):
+                    return True
+            except OSError:
+                time.sleep(0.1)
+        return False
+
+    def stop(self) -> None:
+        if self._server is not None:
+            self._server.should_exit = True
+        if self._thread is not None and self._thread.is_alive():
+            self._thread.join(timeout=5)
+
+
+@pytest.fixture(scope="module")
+def server_url() -> Generator[str, None, None]:
+    """Start one local app server per Playwright test module."""
+    server = ServerManager(find_free_port())
+    server.start()
+    try:
+        yield server.url
+    finally:
+        server.stop()
+
+
+@pytest.fixture(scope="module")
+def base_url(server_url: str) -> str:
+    """Alias used by browser tests."""
+    return server_url
+
 
 @pytest.fixture
 def sample_portfolio() -> LombardPortfolio: