Added unittest cases to managed command parallel test.

docs/ref/django-admin.txt

@@ -1477,7 +1477,7 @@ Using ``--parallel`` without a value, or with the value ``auto``, runs one test
 process per core according to :func:`multiprocessing.cpu_count()`. You can
 override this by passing the desired number of processes, e.g.
 ``--parallel 4``, or by setting the :envvar:`DJANGO_TEST_PROCESSES` environment
-variable.
+variable. If both are given, then ``--parallel 4`` takes precedence.
 
 Django distributes test cases — :class:`unittest.TestCase` subclasses — to
 subprocesses. If there are fewer test cases than configured processes, Django

tests/test_runner/tests.py

@@ -550,6 +550,16 @@ class ManageCommandParallelTests(SimpleTestCase):
                     )
                 self.assertIn("parallel=7", stderr.getvalue())
 
+    @mock.patch.dict(os.environ, {"DJANGO_TEST_PROCESSES": "7"})
+    def test_django_test_processes_parallel_override_env(self, *mocked_objects):
+        with captured_stderr() as stderr:
+            call_command(
+                "test",
+                "--parallel=8",
+                testrunner="test_runner.tests.MockTestRunner",
+            )
+        self.assertIn("parallel=8", stderr.getvalue())
+
 
 class CustomTestRunnerOptionsSettingsTests(AdminScriptTestCase):
     """