diff --git a/lib/matplotlib/tests/test_backend_qt.py b/lib/matplotlib/tests/test_backend_qt.py
index 6a938aece43d..a9ffc69eeeae 100644
--- a/lib/matplotlib/tests/test_backend_qt.py
+++ b/lib/matplotlib/tests/test_backend_qt.py
@@ -206,23 +206,23 @@ def CustomHandler(signum, frame):
 ])
 def test_correct_key(backend, qt_key, qt_mods, answer):
     """
-    Make a figure
-    Send a key_press_event event (using non-public, qtX backend specific api)
-    Catch the event
-    Assert sent and caught keys are the same
+    Make a figure.
+    Send a key_press_event event (using non-public, qtX backend specific api).
+    Catch the event.
+    Assert sent and caught keys are the same.
     """
     qt_canvas = plt.figure().canvas
 
-    event = mock.Mock()
-    event.isAutoRepeat.return_value = False
-    event.key.return_value = qt_key
-    event.modifiers.return_value = qt_mods
+    class _Event:
+        def isAutoRepeat(self): return False
+        def key(self): return qt_key
+        def modifiers(self): return qt_mods
 
     def receive(event):
         assert event.key == answer
 
     qt_canvas.mpl_connect('key_press_event', receive)
-    qt_canvas.keyPressEvent(event)
+    qt_canvas.keyPressEvent(_Event())
 
 
 @pytest.mark.backend('Qt5Agg')
diff --git a/lib/matplotlib/tests/test_dates.py b/lib/matplotlib/tests/test_dates.py
index 670f3bed7ec3..b891daa1131f 100644
--- a/lib/matplotlib/tests/test_dates.py
+++ b/lib/matplotlib/tests/test_dates.py
@@ -1,6 +1,5 @@
 import datetime
 import tempfile
-from unittest.mock import Mock
 
 import dateutil.tz
 import dateutil.rrule
@@ -245,12 +244,14 @@ def test_locator_set_formatter():
 
 
 def test_date_formatter_callable():
-    scale = -11
-    locator = Mock(_get_unit=Mock(return_value=scale))
-    callable_formatting_function = (lambda dates, _:
-                                    [dt.strftime('%d-%m//%Y') for dt in dates])
 
-    formatter = mdates.AutoDateFormatter(locator)
+    class _Locator:
+        def _get_unit(self): return -11
+
+    def callable_formatting_function(dates, _):
+        return [dt.strftime('%d-%m//%Y') for dt in dates]
+
+    formatter = mdates.AutoDateFormatter(_Locator())
     formatter.scaled[-10] = callable_formatting_function
     assert formatter([datetime.datetime(2014, 12, 25)]) == ['25-12//2014']
 
diff --git a/lib/matplotlib/tests/test_widgets.py b/lib/matplotlib/tests/test_widgets.py
index 9a6744d07815..94356621e777 100644
--- a/lib/matplotlib/tests/test_widgets.py
+++ b/lib/matplotlib/tests/test_widgets.py
@@ -1,4 +1,4 @@
-from unittest.mock import Mock
+from types import SimpleNamespace
 
 import matplotlib.widgets as widgets
 import matplotlib.pyplot as plt
@@ -54,7 +54,7 @@ def do_event(tool, etype, button=1, xdata=0, ydata=0, key=None, step=1):
     *step*
         number of scroll steps (positive for 'up', negative for 'down')
     """
-    event = Mock()
+    event = SimpleNamespace()
     event.button = button
     ax = tool.ax
     event.x, event.y = ax.transData.transform([(xdata, ydata),