[fix] unit tests: fix load / unload engines & fix messages

- https://github.com/searxng/searxng/pull/3746#issuecomment-2300965005
- https://github.com/searxng/searxng/issues/2988#issuecomment-2226929084

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

tests/unit/test_webapp.py

@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
 # pylint: disable=missing-module-docstring
 
+import logging
 import json
 from urllib.parse import ParseResult
 from mock import Mock
@@ -20,8 +21,13 @@ class ViewsTestCase(SearxTestCase):  # pylint: disable=missing-class-docstring,
 
         self.setattr4test(searx.search.processors, 'initialize_processor', dummy)
 
+        log = logging.getLogger("searx")
+        log_lev = log.level
+        log.setLevel(logging.ERROR)
         from searx import webapp  # pylint: disable=import-outside-toplevel
 
+        log.setLevel(log_lev)
+
         webapp.app.config['TESTING'] = True  # to get better error messages
         self.app = webapp.app.test_client()