diff --git a/qutebrowser/browser/webengine/webenginetab.py b/qutebrowser/browser/webengine/webenginetab.py
index cf307c93c..db9c4e4b9 100644
--- a/qutebrowser/browser/webengine/webenginetab.py
+++ b/qutebrowser/browser/webengine/webenginetab.py
@@ -76,7 +76,8 @@ def init():
         from qutebrowser.browser.webengine import notification
         log.init.debug("Setting up DBus notification presenter...")
         try:
-            presenter = notification.DBusNotificationPresenter()
+            testing = 'test-notification-service' in objects.debug_flags
+            presenter = notification.DBusNotificationPresenter(testing)
             for p in [webenginesettings.default_profile, webenginesettings.private_profile]:
                 if not p:
                     continue
diff --git a/qutebrowser/qutebrowser.py b/qutebrowser/qutebrowser.py
index 0ffdb5567..327388e75 100644
--- a/qutebrowser/qutebrowser.py
+++ b/qutebrowser/qutebrowser.py
@@ -172,11 +172,12 @@ def debug_flag_error(flag):
         stack: Enable Chromium stack logging.
         chromium: Enable Chromium logging.
         werror: Turn Python warnings into errors.
+        test-notification-service: Use the testing libnotify service.
     """
     valid_flags = ['debug-exit', 'pdb-postmortem', 'no-sql-history',
                    'no-scroll-filtering', 'log-requests', 'log-cookies',
                    'lost-focusproxy', 'log-scroll-pos', 'stack', 'chromium',
-                   'werror']
+                   'werror', 'test-notification-service']
 
     if flag in valid_flags:
         return flag
diff --git a/tests/end2end/conftest.py b/tests/end2end/conftest.py
index 273d8170c..7190c7ef4 100644
--- a/tests/end2end/conftest.py
+++ b/tests/end2end/conftest.py
@@ -34,6 +34,7 @@ from PyQt5.QtCore import PYQT_VERSION
 
 pytest.register_assert_rewrite('end2end.fixtures')
 
+from end2end.fixtures.notificationserver import notification_server
 from end2end.fixtures.webserver import server, server_per_test, ssl_server
 from end2end.fixtures.quteprocess import (quteproc_process, quteproc,
                                           quteproc_new)
diff --git a/tests/end2end/fixtures/notificationserver.py b/tests/end2end/fixtures/notificationserver.py
index a1e74753d..9ef7cb77b 100644
--- a/tests/end2end/fixtures/notificationserver.py
+++ b/tests/end2end/fixtures/notificationserver.py
@@ -21,24 +21,28 @@ class TestNotificationServer(QObject):
     def __init__(self, service: str):
         # Note that external users should call get() instead.
         super().__init__()
-        self.service = service
-        self.bus = QDBusConnection.sessionBus()
+        self._service = service
+        self._bus = QDBusConnection.sessionBus()
+        self._message_id = 0
+        # A list of all the messages that we've received. Test code should
+        # inspect this to make sure messages get delivered.
         self.messages = []  # type: typing.List[QDBusMessage]
 
     def register(self) -> None:
-        assert self.bus.registerService(self.service)
-        assert self.registerObject(DBusNotificationPresenter.PATH,
+        assert self._bus.registerService(self._service)
+        assert self._bus.registerObject(DBusNotificationPresenter.PATH,
                             DBusNotificationPresenter.INTERFACE,
                             self,
                             QDBusConnection.ExportAllSlots)
 
     def unregister(self) -> None:
-        assert self.bus.unregisterService(self.service)
-        self.messages = []
+        assert self._bus.unregisterService(self._service)
 
-    @pyqtSlot(QDBusMessage)
-    def Notify(self, message: QDBusMessage) -> None:
+    @pyqtSlot(QDBusMessage, result="uint")
+    def Notify(self, message: QDBusMessage) -> QDBusArgument:
+        self._message_id += 1
         self.messages.append(message)
+        return self._message_id
 
     def close(self, notification_id: int) -> None:
         """Sends a close notification for the given ID."""
@@ -46,8 +50,10 @@ class TestNotificationServer(QObject):
             DBusNotificationPresenter.PATH,
             DBusNotificationPresenter.INTERFACE,
             "NotificationClosed")
+        # the 2 here is the notification removal reason; it's effectively
+        # arbitrary
         message.setArguments([_as_uint32(notification_id), _as_uint32(2)])
-        if not self.bus.send(message):
+        if not self._bus.send(message):
             raise IOError("Could not send close notification")
 
 @pytest.fixture
@@ -60,6 +66,6 @@ def notification_server(qapp):
 
 def _as_uint32(x: int) -> QVariant:
     variant = QVariant(x)
-    variant.convert(QVariant.UInt)
+    assert variant.convert(QVariant.UInt)
     return variant
 
diff --git a/tests/end2end/fixtures/quteprocess.py b/tests/end2end/fixtures/quteprocess.py
index 5f8263334..a8af02d19 100644
--- a/tests/end2end/fixtures/quteprocess.py
+++ b/tests/end2end/fixtures/quteprocess.py
@@ -526,7 +526,8 @@ class QuteProc(testprocess.Process):
         args = ['--debug', '--no-err-windows', '--temp-basedir',
                 '--json-logging', '--loglevel', 'vdebug',
                 '--backend', backend, '--debug-flag', 'no-sql-history',
-                '--debug-flag', 'werror']
+                '--debug-flag', 'werror', '--debug-flag',
+                'test-notification-service']
         if qVersion() == '5.7.1':
             # https://github.com/qutebrowser/qutebrowser/issues/3163
             args += ['--qt-flag', 'disable-seccomp-filter-sandbox']
@@ -983,7 +984,7 @@ def quteproc_process(qapp, server, request):
 
 
 @pytest.fixture
-def quteproc(quteproc_process, server, request):
+def quteproc(quteproc_process, server, request, notification_server):
     """Per-test qutebrowser fixture which uses the per-file process."""
     request.node._quteproc_log = quteproc_process.captured_log
     quteproc_process.before_test()