fix: guard missing env vars in authenticate(), drain queues post-yield

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

server.py

@@ -50,6 +50,11 @@ def authenticate() -> str:
     """Initiate Garmin authentication using credentials from environment variables."""
     global _client, _auth_state
 
+    email = os.environ.get("GARMIN_EMAIL", "")
+    password = os.environ.get("GARMIN_PASSWORD", "")
+    if not email or not password:
+        return "GARMIN_EMAIL and GARMIN_PASSWORD environment variables are required."
+
     def _do_login() -> None:
         try:
             _client.login()
@@ -57,7 +62,7 @@ def authenticate() -> str:
         except Exception as exc:
             _login_result_queue.put(("error", str(exc)))
 
-    _client = Garmin(os.environ.get("GARMIN_EMAIL", ""), os.environ.get("GARMIN_PASSWORD", ""))
+    _client = Garmin(email, password)
     _client.prompt_mfa = _prompt_mfa
     threading.Thread(target=_do_login, daemon=True).start()
 

tests/test_server.py

@@ -1,4 +1,5 @@
 import json
+import os
 import queue
 import threading
 from unittest.mock import MagicMock, patch
@@ -21,6 +22,12 @@ def reset_state():
     yield
     server._auth_state = original_state
     server._client = original_client
+    for q in (server._mfa_input_queue, server._login_result_queue):
+        while not q.empty():
+            try:
+                q.get_nowait()
+            except queue.Empty:
+                break
 
 
 def test_check_auth_unauthenticated():
@@ -34,6 +41,8 @@ def test_check_auth_authenticated():
 
 
 def test_authenticate_success():
+    env = {"GARMIN_EMAIL": "test@example.com", "GARMIN_PASSWORD": "secret"}
+    with patch.dict("os.environ", env):
         with patch("server.Garmin") as mock_garmin_cls:
             mock_garmin_cls.return_value = MagicMock()
             # mock login() returns immediately, thread puts success in queue
@@ -43,6 +52,8 @@ def test_authenticate_success():
 
 
 def test_authenticate_mfa_required():
+    env = {"GARMIN_EMAIL": "test@example.com", "GARMIN_PASSWORD": "secret"}
+    with patch.dict("os.environ", env):
         with patch("server.Garmin") as mock_garmin_cls:
             mock_garmin_cls.return_value = MagicMock()
             with patch.object(server._login_result_queue, "get", side_effect=queue.Empty):
@@ -64,3 +75,12 @@ def test_complete_mfa_not_in_progress():
     server._auth_state = "unauthenticated"
     result = server.complete_mfa("123456")
     assert result == "No MFA in progress. Call authenticate() first."
+
+
+def test_authenticate_missing_credentials():
+    with patch.dict("os.environ", {}, clear=False):
+        # Ensure the env vars are absent
+        os.environ.pop("GARMIN_EMAIL", None)
+        os.environ.pop("GARMIN_PASSWORD", None)
+        result = server.authenticate()
+    assert result == "GARMIN_EMAIL and GARMIN_PASSWORD environment variables are required."