diff --git a/Doc/library/unittest.rst b/Doc/library/unittest.rst
index d1a977fd7da6a5..a7c74cfa4fb477 100644
--- a/Doc/library/unittest.rst
+++ b/Doc/library/unittest.rst
@@ -2191,10 +2191,6 @@ Loading and running tests
    .. versionadded:: 3.12
       Added *durations* keyword argument.
 
-   .. versionchanged:: 3.12
-      Subclasses should accept ``**kwargs`` to ensure compatibility as the
-      interface changes.
-
 .. data:: defaultTestLoader
 
    Instance of the :class:`TestLoader` class intended to be shared.  If no
diff --git a/Lib/test/test_unittest/test_runner.py b/Lib/test/test_unittest/test_runner.py
index 1ce42a106c5883..ceb4c8acde532c 100644
--- a/Lib/test/test_unittest/test_runner.py
+++ b/Lib/test/test_unittest/test_runner.py
@@ -1367,7 +1367,7 @@ def testSpecifiedStreamUsed(self):
         self.assertTrue(runner.stream.stream is f)
 
     def test_durations(self):
-        def run(test, expect_durations):
+        def run(test, *, expect_durations=True):
             stream = BufferedWriter()
             runner = unittest.TextTestRunner(stream=stream, durations=5, verbosity=2)
             result = runner.run(test)
@@ -1389,21 +1389,21 @@ class Foo(unittest.TestCase):
             def test_1(self):
                 pass
 
-        run(Foo('test_1'), True)
+        run(Foo('test_1'), expect_durations=True)
 
         # failure
         class Foo(unittest.TestCase):
             def test_1(self):
                 self.assertEqual(0, 1)
 
-        run(Foo('test_1'), True)
+        run(Foo('test_1'), expect_durations=True)
 
         # error
         class Foo(unittest.TestCase):
             def test_1(self):
                 1 / 0
 
-        run(Foo('test_1'), True)
+        run(Foo('test_1'), expect_durations=True)
 
 
         # error in setUp and tearDown
@@ -1414,7 +1414,7 @@ def setUp(self):
             def test_1(self):
                 pass
 
-        run(Foo('test_1'), True)
+        run(Foo('test_1'), expect_durations=True)
 
         # skip (expect no durations)
         class Foo(unittest.TestCase):
@@ -1422,7 +1422,7 @@ class Foo(unittest.TestCase):
             def test_1(self):
                 pass
 
-        run(Foo('test_1'), False)
+        run(Foo('test_1'), expect_durations=False)
 
 
 
diff --git a/Lib/unittest/result.py b/Lib/unittest/result.py
index fa9bea47c88829..7757dba9670b43 100644
--- a/Lib/unittest/result.py
+++ b/Lib/unittest/result.py
@@ -159,7 +159,11 @@ def addUnexpectedSuccess(self, test):
         self.unexpectedSuccesses.append(test)
 
     def addDuration(self, test, elapsed):
-        """Called when a test finished to run, regardless of its outcome."""
+        """Called when a test finished to run, regardless of its outcome.
+        *test* is the test case corresponding to the test method.
+        *elapsed* is the time represented in seconds, and it includes the
+        execution of cleanup functions.
+        """
         # support for a TextTestRunner using an old TestResult class
         if hasattr(self, "collectedDurations"):
             self.collectedDurations.append((test, elapsed))