Fix django parallel test runner's elapsed time reporting on python 3.12 or higher

tests/testsuite.py

@@ -240,8 +240,18 @@ def _test_xmlrunner(self, suite, runner=None, outdir=None):
         runner.run(suite)
         if isinstance(outdir, BytesIO):
             self.assertTrue(outdir.getvalue())
+            xml_content = outdir.getvalue()
         else:
-            self.assertEqual(1, len(glob(os.path.join(outdir, '*xml'))))
+            xml_files = glob(os.path.join(outdir, '*xml'))
+            self.assertEqual(1, len(xml_files))
+            with open(xml_files[0], 'rb') as f:
+                xml_content = f.read()
+
+        doc = minidom.parseString(xml_content)
+        for testcase in doc.getElementsByTagName('testcase'):
+            elapsed = float(testcase.getAttribute('time'))
+            self.assertGreaterEqual(elapsed, 0.0)
+
         return runner
 
     def test_basic_unittest_constructs(self):
@@ -903,6 +913,15 @@ class TestWithPartialmethod(unittest.TestCase):
         suite.addTest(TestWithPartialmethod('test_partialmethod'))
         self._test_xmlrunner(suite)
 
+    def test_elapsed_time_with_docstring(self):
+        class DocstringTest(unittest.TestCase):
+            def test_with_doc(self):
+                """This test has a docstring."""
+                pass
+
+        suite = unittest.TestSuite()
+        suite.addTest(DocstringTest('test_with_doc'))
+        self._test_xmlrunner(suite)
 
 
 class DuplicateWriterTestCase(unittest.TestCase):

xmlrunner/result.py

@@ -167,10 +167,12 @@ def __init__(self, test_result, test_method, outcome=SUCCESS, err=None, subTest=
 
         self.test_name = testcase_name(test_method)
         self.test_id = test_method.id()
+        self.test_str = str(test_method)
 
         if subTest:
             self.test_id = subTest.id()
             self.test_description = self.test_result.getDescription(subTest)
+            self.test_str = str(subTest)
 
         self.filename = filename
         self.lineno = lineno
@@ -179,11 +181,25 @@ def __init__(self, test_result, test_method, outcome=SUCCESS, err=None, subTest=
     def id(self):
         return self.test_id
 
+    def _get_elapsed_time(self):
+        """Return elapsed time from addDuration (3.12+) or start/stop delta.
+
+        In parallel test runners like Django's, startTest/stopTest events are 
+        replayed in the parent process, making stop_time - start_time near-zero. 
+        Python 3.12's addDuration carries the real worker-measured elapsed time
+        correctly allowing us to prevent this issue for 3.12+.
+        """
+        collected = getattr(self.test_result, 'collectedDurations', [])
+        for test_repr, elapsed in reversed(collected):
+            if test_repr == self.test_str:
+                return elapsed
+
+        return self.test_result.stop_time - self.test_result.start_time
+
     def test_finished(self):
         """Save info that can only be calculated once a test has run.
         """
-        self.elapsed_time = \
-            self.test_result.stop_time - self.test_result.start_time
+        self.elapsed_time = self._get_elapsed_time()
         timestamp = datetime.datetime.fromtimestamp(self.test_result.stop_time)
         self.timestamp = timestamp.replace(microsecond=0).isoformat()