diff --git a/tests/_test_msui/conftest.py b/tests/_test_msui/conftest.py
new file mode 100644
index 000000000..6ccfa2ffb
--- /dev/null
+++ b/tests/_test_msui/conftest.py
@@ -0,0 +1,35 @@
+# -*- coding: utf-8 -*-
+"""
+
+    tests._test_msui.conftest
+    ~~~~~~~~~~~~~~~~~~~~~~~~~
+
+    common definitions for _test_msui
+
+    This file is part of MSS.
+
+    :copyright: Copyright 2016-2017 Reimar Bauer
+    :copyright: Copyright 2016-2026 by the MSS team, see AUTHORS.
+    :license: APACHE-2.0, see LICENSE for details.
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+"""
+import pytest
+from mslib.utils.service_manager import WMSServiceManager
+
+
+@pytest.fixture(autouse=True)
+def _reset_wms_service_manager():
+    WMSServiceManager._shared_cache.clear()
+    yield
+    WMSServiceManager._shared_cache.clear()
diff --git a/tests/_test_msui/test_wms_control.py b/tests/_test_msui/test_wms_control.py
index 219964c04..4bb238f52 100644
--- a/tests/_test_msui/test_wms_control.py
+++ b/tests/_test_msui/test_wms_control.py
@@ -33,7 +33,6 @@
 import eventlet
 from PyQt5 import QtCore, QtTest
 from mslib.msui import flighttrack as ft
-from mslib.utils.service_manager import WMSServiceManager
 import mslib.msui.wms_control as wc
 
 
@@ -57,8 +56,6 @@ def _with_mswms_server(self, mswms_server):
         self.scheme, self.host, self.port = parsed_url.scheme, parsed_url.hostname, parsed_url.port
 
     def _setup(self, widget_type, tmp_path):
-        self.service_manager = WMSServiceManager()
-        self.service_manager.clear_cache()
         if widget_type == "hsec":
             self.view = HSecViewMockup()
         else:
@@ -500,8 +497,6 @@ class TestWMSControlWidgetSetupSimple:
 
     @pytest.fixture(autouse=True)
     def setup(self, tmp_path, qtbot):
-        self.service_manager = WMSServiceManager()
-        self.service_manager.clear_cache()
         self.view = HSecViewMockup()
         self.tempdir = tmp_path
         self.window = wc.HSecWMSControlWidget(view=self.view, wms_cache=self.tempdir)