gh-131178: Add tests for profile module command-line interface

Add a new `ProfileCLITest` class to `Lib/test/test_profile.py` with
tests covering the full CLI surface of the `profile` module:

- No arguments prints usage and exits with code 2
- `-h`/`--help` prints usage and exits with code 0
- Profiling a script file directly
- `-m` flag to profile a library module
- `-m` flag with a non-existent module (failure case)
- `-o`/`--outfile` writes a valid pstats file
- `-s`/`--sort` accepts a sort key without error
- `-m` alone without a module name (failure case)

Co-authored-by: Nityahapani <nityah@users.noreply.github.com>

Author: Nityah

Lib/test/test_profile.py

@@ -135,6 +135,85 @@ def test_output_file_when_changing_directory(self):
             self.assertTrue(os.path.exists('out.pstats'))
 
 
+class ProfileCLITest(unittest.TestCase):
+    """Tests for the profile module command-line interface."""
+
+    def _module_name(self):
+        return 'profile'
+
+    def test_no_args_prints_usage(self):
+        # Running with no arguments should print usage and exit with code 2
+        rc, out, err = assert_python_failure('-m', self._module_name())
+        self.assertEqual(rc, 2)
+
+    def test_help(self):
+        # -h / --help should print usage and exit with code 0
+        rc, out, err = assert_python_ok('-m', self._module_name(), '-h')
+        output = out.decode()
+        self.assertIn('profile', output.lower())
+
+    def test_profile_script(self):
+        # Profile a simple inline script via a temp file
+        with temp_dir() as tmpdir:
+            script = os.path.join(tmpdir, 'hello.py')
+            with open(script, 'w', encoding='utf-8') as f:
+                f.write('x = 1 + 1\n')
+            rc, out, err = assert_python_ok(
+                '-m', self._module_name(), script
+            )
+            self.assertEqual(rc, 0)
+
+    def test_profile_module(self):
+        # -m flag should profile a library module
+        rc, out, err = assert_python_ok(
+            '-m', self._module_name(), '-m', 'timeit', '-n', '1'
+        )
+        self.assertEqual(rc, 0)
+
+    def test_profile_module_missing(self):
+        # -m with a non-existent module should fail
+        rc, out, err = assert_python_failure(
+            '-m', self._module_name(), '-m', 'nonexistent_module_xyz'
+        )
+        self.assertNotEqual(rc, 0)
+
+    def test_output_file(self):
+        # -o should write stats to a file
+        with temp_dir() as tmpdir:
+            outfile = os.path.join(tmpdir, 'stats.pstats')
+            script = os.path.join(tmpdir, 'hello.py')
+            with open(script, 'w', encoding='utf-8') as f:
+                f.write('x = 1 + 1\n')
+            rc, out, err = assert_python_ok(
+                '-m', self._module_name(),
+                '-o', outfile,
+                script,
+            )
+            self.assertEqual(rc, 0)
+            self.assertTrue(os.path.exists(outfile))
+            # The output file should be a valid pstats file
+            stats = pstats.Stats(outfile)
+            self.assertIsNotNone(stats)
+
+    def test_sort_option(self):
+        # -s / --sort should accept a valid sort key without error
+        with temp_dir() as tmpdir:
+            script = os.path.join(tmpdir, 'hello.py')
+            with open(script, 'w', encoding='utf-8') as f:
+                f.write('x = 1 + 1\n')
+            rc, out, err = assert_python_ok(
+                '-m', self._module_name(), '-s', 'cumulative', script
+            )
+            self.assertEqual(rc, 0)
+
+    def test_m_flag_requires_argument(self):
+        # -m alone (with no module name) should fail
+        rc, out, err = assert_python_failure(
+            '-m', self._module_name(), '-m'
+        )
+        self.assertNotEqual(rc, 0)
+
+
 def regenerate_expected_output(filename, cls):
     filename = filename.rstrip('co')
     print('Regenerating %s...' % filename)

Misc/NEWS.d/next/Tests/2026-10-01-12-00-00.gh-issue-131178.aBcDeF.rst

@@ -0,0 +1,3 @@
+Add tests for the :mod:`profile` module's command-line interface, covering
+``--help``, ``-s``/``--sort``, ``-o``/``--outfile``, ``-m`` (module mode),
+no-argument usage, and profiling a script file directly.