diff --git a/tests/helpers/test_stubs.py b/tests/helpers/test_stubs.py
index 10fa9e5db..a5c1d27fb 100644
--- a/tests/helpers/test_stubs.py
+++ b/tests/helpers/test_stubs.py
@@ -36,8 +36,8 @@ def test_timeout(timer):
     func2 = mock.Mock()
     timer.timeout.connect(func)
     timer.timeout.connect(func2)
-    assert not func.called
-    assert not func2.called
+    func.assert_not_called()
+    func2.assert_not_called()
     timer.timeout.emit()
     func.assert_called_once_with()
     func2.assert_called_once_with()
@@ -49,7 +49,7 @@ def test_disconnect_all(timer):
     timer.timeout.connect(func)
     timer.timeout.disconnect()
     timer.timeout.emit()
-    assert not func.called
+    func.assert_not_called()
 
 
 def test_disconnect_one(timer):
@@ -58,7 +58,7 @@ def test_disconnect_one(timer):
     timer.timeout.connect(func)
     timer.timeout.disconnect(func)
     timer.timeout.emit()
-    assert not func.called
+    func.assert_not_called()
 
 
 def test_disconnect_all_invalid(timer):
@@ -74,8 +74,8 @@ def test_disconnect_one_invalid(timer):
     timer.timeout.connect(func1)
     with pytest.raises(TypeError):
         timer.timeout.disconnect(func2)
-    assert not func1.called
-    assert not func2.called
+    func1.assert_not_called()
+    func2.assert_not_called()
     timer.timeout.emit()
     func1.assert_called_once_with()
 
diff --git a/tests/unit/completion/test_completionmodel.py b/tests/unit/completion/test_completionmodel.py
index 9e73e533a..292349730 100644
--- a/tests/unit/completion/test_completionmodel.py
+++ b/tests/unit/completion/test_completionmodel.py
@@ -103,7 +103,7 @@ def test_delete_cur_item_no_func():
     parent = model.index(0, 0)
     with pytest.raises(cmdexc.CommandError):
         model.delete_cur_item(model.index(0, 0, parent))
-    assert not callback.called
+    callback.assert_not_called()
 
 
 def test_delete_cur_item_no_cat():
@@ -114,4 +114,4 @@ def test_delete_cur_item_no_cat():
     model.rowsRemoved.connect(callback)
     with pytest.raises(qtutils.QtValueError):
         model.delete_cur_item(QModelIndex())
-    assert not callback.called
+    callback.assert_not_called()
diff --git a/tests/unit/completion/test_completionwidget.py b/tests/unit/completion/test_completionwidget.py
index 7eb7fe2b5..22c71a2b7 100644
--- a/tests/unit/completion/test_completionwidget.py
+++ b/tests/unit/completion/test_completionwidget.py
@@ -242,7 +242,7 @@ def test_completion_item_del_no_selection(completionview):
     completionview.set_model(model)
     with pytest.raises(cmdexc.CommandError, match='No item selected!'):
         completionview.completion_item_del()
-    assert not func.called
+    func.assert_not_called()
 
 
 def test_resize_no_model(completionview, qtbot):
diff --git a/tests/unit/config/test_configinit.py b/tests/unit/config/test_configinit.py
index fef352584..767ffd6ca 100644
--- a/tests/unit/config/test_configinit.py
+++ b/tests/unit/config/test_configinit.py
@@ -151,7 +151,7 @@ def test_late_init(init_patch, monkeypatch, fake_save_manager, fake_args,
         assert text.startswith('Errors occurred while reading config.py:')
         assert '<b>Error text</b>: Exception' in text
     else:
-        assert not msgbox_mock.called
+        msgbox_mock.assert_not_called()
 
 
 class TestQtArgs:
diff --git a/tests/unit/misc/test_ipc.py b/tests/unit/misc/test_ipc.py
index d8024b207..874419511 100644
--- a/tests/unit/misc/test_ipc.py
+++ b/tests/unit/misc/test_ipc.py
@@ -380,7 +380,7 @@ class TestHandleConnection:
         monkeypatch.setattr(ipc_server._server, 'nextPendingConnection', m)
         ipc_server.ignored = True
         ipc_server.handle_connection()
-        assert not m.called
+        m.assert_not_called()
 
     def test_no_connection(self, ipc_server, caplog):
         ipc_server.handle_connection()
diff --git a/tests/unit/utils/test_standarddir.py b/tests/unit/utils/test_standarddir.py
index 3dcb282d2..20ea88645 100644
--- a/tests/unit/utils/test_standarddir.py
+++ b/tests/unit/utils/test_standarddir.py
@@ -494,17 +494,17 @@ def test_init(mocker, tmpdir, args_kind):
     assert standarddir._locations != {}
     if args_kind == 'normal':
         if utils.is_mac:
-            assert not m_windows.called
+            m_windows.assert_not_called()
             assert m_mac.called
         elif utils.is_windows:
             assert m_windows.called
-            assert not m_mac.called
+            m_mac.assert_not_called()
         else:
-            assert not m_windows.called
-            assert not m_mac.called
+            m_windows.assert_not_called()
+            m_mac.assert_not_called()
     else:
-        assert not m_windows.called
-        assert not m_mac.called
+        m_windows.assert_not_called()
+        m_mac.assert_not_called()
 
 
 @pytest.mark.linux