gh-131178: Add tests for mimetypes command-line interface

Author: htjworld

Lib/test/test_mimetypes.py

@@ -6,8 +6,9 @@
 import unittest.mock
 from platform import win32_edition
 from test import support
-from test.support import cpython_only, force_not_colorized, os_helper
+from test.support import cpython_only, force_not_colorized, os_helper, requires_subprocess
 from test.support.import_helper import ensure_lazy_imports
+from test.support.script_helper import assert_python_ok, assert_python_failure
 
 try:
     import _winapi
@@ -508,5 +509,51 @@ def test_invocation_error(self):
                 self.assertEqual(result, expected)
 
 
+@requires_subprocess()
+class CommandLineSubprocessTest(unittest.TestCase):
+    def test_help(self):
+        rc, stdout, stderr = assert_python_ok('-m', 'mimetypes', '--help')
+        self.assertIn(b'mimetypes', stdout)
+        self.assertIn(b'--help', stdout)
+        self.assertIn(b'--extension', stdout)
+        self.assertIn(b'--lenient', stdout)
+
+    def test_type_lookup(self):
+        rc, stdout, stderr = assert_python_ok('-m', 'mimetypes', 'foo.pdf')
+        self.assertIn(b'application/pdf', stdout)
+
+    def test_type_lookup_unknown(self):
+        rc, stdout, stderr = assert_python_failure('-m', 'mimetypes', 'foo.unknownext12345')
+        self.assertIn(b'error:', stdout)
+
+    def test_extension_flag(self):
+        rc, stdout, stderr = assert_python_ok('-m', 'mimetypes', '-e', 'image/jpeg')
+        self.assertIn(b'.jpg', stdout)
+
+    def test_extension_flag_unknown(self):
+        rc, stdout, stderr = assert_python_failure('-m', 'mimetypes', '-e', 'image/unknowntype12345')
+        self.assertIn(b'error:', stdout)
+
+    def test_lenient_flag(self):
+        rc, stdout, stderr = assert_python_ok('-m', 'mimetypes', '--lenient', 'foo.webp')
+        self.assertIn(b'image/webp', stdout)
+
+    def test_multiple_inputs(self):
+        rc, stdout, stderr = assert_python_ok('-m', 'mimetypes', 'foo.pdf', 'foo.png')
+        self.assertIn(b'application/pdf', stdout)
+        self.assertIn(b'image/png', stdout)
+
+    def test_multiple_inputs_with_error(self):
+        rc, stdout, stderr = assert_python_failure(
+            '-m', 'mimetypes', 'foo.pdf', 'foo.unknownext12345'
+        )
+        self.assertIn(b'application/pdf', stdout)
+        self.assertIn(b'error:', stdout)
+
+    def test_unknown_flag(self):
+        rc, stdout, stderr = assert_python_failure('-m', 'mimetypes', '--unknown-flag')
+        self.assertNotEqual(rc, 0)
+
+
 if __name__ == "__main__":
     unittest.main()

Misc/NEWS.d/next/Tests/2026-05-11-23-26-02.gh-issue-131178.Y2o6Dt.rst

@@ -0,0 +1 @@
+Add tests for the :mod:`mimetypes` command-line interface.